diff --git a/Recyclable.Collections/RecyclableList.AddRange.cs b/Recyclable.Collections/RecyclableList.AddRange.cs
new file mode 100644
index 0000000..2f153c0
--- /dev/null
+++ b/Recyclable.Collections/RecyclableList.AddRange.cs
@@ -0,0 +1,322 @@
+using System;
+using System.Collections;
+using System.Collections.Generic;
+using System.Linq;
+using System.Numerics;
+using System.Runtime.CompilerServices;
+using System.Threading.Tasks;
+
+namespace Recyclable.Collections
+{
+    public static class zRecyclableListAddRange
+    {
+		private static void AddRangeEnumerated<T>(this RecyclableList<T> list, IEnumerable<T> items, int growByCount)
+		{
+			int targetItemIndex = list._count;
+			Span<T> memorySpan;
+
+			int i;
+			var enumerator = items.GetEnumerator();
+
+			int capacity = list._capacity;
+			memorySpan = new(list._memoryBlock);
+			if (enumerator.MoveNext())
+			{
+				int available = capacity - targetItemIndex;
+				do
+				{
+					if (targetItemIndex + growByCount > capacity)
+					{
+						capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, targetItemIndex, checked((int)BitOperations.RoundUpToPowerOf2((uint)(targetItemIndex + growByCount))));
+						memorySpan = new(list._memoryBlock);
+						available = capacity - targetItemIndex;
+					}
+
+					for (i = 0; i < available; i++)
+					{
+						memorySpan[targetItemIndex++] = enumerator.Current;
+						if (!enumerator.MoveNext())
+						{
+							break;
+						}
+					}
+				}
+				while (i >= available);
+			}
+
+			list._capacity = capacity;
+			list._count = targetItemIndex;
+		}
+
+		private static void AddRangeWithKnownCount<T>(this RecyclableList<T> list, IEnumerable<T> items, int currentItemsCount, int requiredAdditionalCapacity)
+		{
+			list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, currentItemsCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)(currentItemsCount + requiredAdditionalCapacity))));
+
+			Span<T> memorySpan = new(list._memoryBlock);
+			foreach (var item in items)
+			{
+				memorySpan[currentItemsCount++] = item;
+			}
+
+			list._count = currentItemsCount;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, in Array items)
+		{
+			if (list._capacity < list._count + items.Length)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Length))));
+			}
+
+			Array.Copy(items, items.GetLowerBound(0), list._memoryBlock, list._count, items.LongLength);
+			list._count += items.Length;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, in T[] items)
+		{
+			if (list._capacity < list._count + items.Length)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Length))));
+			}
+
+			new Span<T>(items).CopyTo(new Span<T>(list._memoryBlock, list._count, items.Length));
+			list._count += items.Length;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, ReadOnlySpan<T> items)
+		{
+			if (list._capacity < list._count + items.Length)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Length))));
+			}
+
+			items.CopyTo(new Span<T>(list._memoryBlock, list._count, items.Length));
+			list._count += items.Length;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, Span<T> items)
+		{
+			if (list._capacity < list._count + items.Length)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Length))));
+			}
+
+			items.CopyTo(new Span<T>(list._memoryBlock, list._count, items.Length));
+			list._count += items.Length;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, List<T> items)
+		{
+			if (list._capacity < list._count + items.Count)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Count))));
+			}
+
+			items.CopyTo(list._memoryBlock, list._count);
+			list._count += items.Count;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, ICollection items)
+		{
+			if (list._capacity < list._count + items.Count)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Count))));
+			}
+
+			items.CopyTo(list._memoryBlock, list._count);
+			list._count += items.Count;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, ICollection<T> items)
+		{
+			if (list._capacity < list._count + items.Count)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items.Count))));
+			}
+
+			items.CopyTo(list._memoryBlock, list._count);
+			list._count += items.Count;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, RecyclableList<T> items)
+		{
+			if (list._capacity < list._count + items._count)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + items._count))));
+			}
+
+			new Span<T>(items._memoryBlock, 0, items._count).CopyTo(new Span<T>(list._memoryBlock, list._count, items._count));
+			list._count += items._count;
+			list._version++;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, RecyclableLongList<T> items)
+		{
+			if (items._longCount == 0)
+			{
+				return;
+			}
+
+			int oldCount = list._count;
+			long sourceItemsCount = items._longCount;
+			if (oldCount + sourceItemsCount > int.MaxValue)
+			{
+				ThrowHelper.ThrowArgumentOutOfRangeException(nameof(items), $"The total number of items in source and target table exceeds the maximum capacity of {nameof(RecyclableList<T>)}, equal {int.MaxValue}. Please consider using {nameof(RecyclableLongList<T>)}, instead");
+			}
+
+			int targetCapacity = oldCount + (int)sourceItemsCount;
+			if (list._capacity < targetCapacity)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+			}
+
+			// TODO: Avoid unnecessary range operator - pass as arguments instead.
+			Span<T> targetSpan = new Span<T>(list._memoryBlock)[oldCount..],
+				itemsSpan;
+
+			int blockIndex,
+				sourceBlockSize = items._blockSize,
+				lastBlockIndex = (int)(sourceItemsCount >> items._blockSizePow2BitShift) - 1;
+
+			for (blockIndex = 0; blockIndex <= lastBlockIndex; blockIndex++)
+			{
+				itemsSpan = new(items._memoryBlocks[blockIndex], 0, sourceBlockSize);
+				itemsSpan.CopyTo(targetSpan);
+				targetSpan = targetSpan[sourceBlockSize..];
+			}
+
+			if (blockIndex == 0)
+			{
+				itemsSpan = new(items._memoryBlocks[blockIndex], 0, (int)sourceItemsCount);
+				itemsSpan.CopyTo(targetSpan);
+			}
+			else if (blockIndex <= items._lastBlockWithData)
+			{
+				itemsSpan = new(items._memoryBlocks[blockIndex], 0, items._nextItemIndex);
+				itemsSpan.CopyTo(targetSpan);
+			}
+
+			list._count = targetCapacity;
+			list._version++;
+		}
+
+		public static IEnumerator AddRange<T>(this RecyclableList<T> list, IEnumerable source, int growByCount = RecyclableDefaults.MinPooledArrayLength)
+		{
+			int targetItemIndex = list._count;
+			Span<T> memorySpan;
+
+			int i;
+			var enumerator = source.GetEnumerator();
+
+			int capacity = list._capacity;
+			memorySpan = new(list._memoryBlock);
+			if (enumerator.MoveNext())
+			{
+				int available = capacity - targetItemIndex;
+				do
+				{
+					if (targetItemIndex + growByCount > capacity)
+					{
+						capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, targetItemIndex, checked((int)BitOperations.RoundUpToPowerOf2((uint)(targetItemIndex + growByCount))));
+						memorySpan = new(list._memoryBlock);
+						available = capacity - targetItemIndex;
+					}
+
+					for (i = 0; i < available; i++)
+					{
+						memorySpan[targetItemIndex++] = (T)enumerator.Current;
+						if (!enumerator.MoveNext())
+						{
+							break;
+						}
+					}
+				}
+				while (i >= available);
+			}
+
+			list._capacity = capacity;
+			list._count = targetItemIndex;
+			return enumerator;
+		}
+
+		public static void AddRange<T>(this RecyclableList<T> list, IReadOnlyList<T> items)
+		{
+			int sourceItemsCount = items.Count;
+			if (list._capacity < list._count + sourceItemsCount)
+			{
+				list._capacity = RecyclableListHelpers<T>.ResizeAndCopy(list, list._count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(list._count + sourceItemsCount))));
+			}
+
+			Span<T> memorySpan = new(list._memoryBlock, list._count, sourceItemsCount);
+			for (var sourceItemIndex = 0; sourceItemIndex < sourceItemsCount; sourceItemIndex++)
+			{
+				memorySpan[sourceItemIndex] = items[sourceItemIndex];
+			}
+
+			list._count += sourceItemsCount;
+		}
+
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public static void AddRange<T>(this RecyclableList<T> list, IEnumerable<T> items, int growByCount = RecyclableDefaults.MinPooledArrayLength)
+		{
+			if (items is RecyclableList<T> sourceRecyclableList)
+			{
+				AddRange(list, sourceRecyclableList);
+			}
+			else if (items is RecyclableLongList<T> sourceRecyclableLongList)
+			{
+				AddRange(list, sourceRecyclableLongList);
+			}
+			else if (items is T[] sourceArray)
+			{
+				AddRange(list, sourceArray);
+			}
+			else if (items is Array sourceArrayWithObjects)
+			{
+				AddRange(list, sourceArrayWithObjects);
+			}
+			else if (items is List<T> sourceList)
+			{
+				AddRange(list, sourceList);
+			}
+			else if (items is ICollection<T> sourceICollection)
+			{
+				AddRange(list, sourceICollection);
+			}
+			else if (items is ICollection sourceICollectionWithObjects)
+			{
+				AddRange(list, sourceICollectionWithObjects);
+			}
+			else if (items is IReadOnlyList<T> sourceIReadOnlyList)
+			{
+				AddRange(list, sourceIReadOnlyList);
+			}
+			else if (items.TryGetNonEnumeratedCount(out var requiredAdditionalCapacity) && requiredAdditionalCapacity != 0)
+			{
+				AddRangeWithKnownCount(list, items, list._count, requiredAdditionalCapacity);
+				list._version++;
+			}
+			else
+			{
+				AddRangeEnumerated(list, items, growByCount);
+				list._version++;
+			}
+		}
+    }
+}
\ No newline at end of file
diff --git a/Recyclable.Collections/RecyclableList.cs b/Recyclable.Collections/RecyclableList.cs
index ba6bad6..3d1f34a 100644
--- a/Recyclable.Collections/RecyclableList.cs
+++ b/Recyclable.Collections/RecyclableList.cs
@@ -19,57 +19,6 @@ namespace Recyclable.Collections
 		internal ulong _version;
 		public ulong Version => _version;
 
-		private void AddRangeEnumerated(IEnumerable<T> items, int growByCount)
-		{
-			int targetItemIndex = _count;
-			Span<T> memorySpan;
-
-			int i;
-			var enumerator = items.GetEnumerator();
-
-			int capacity = _capacity;
-			memorySpan = new(_memoryBlock);
-			if (enumerator.MoveNext())
-			{
-				int available = capacity - targetItemIndex;
-				do
-				{
-					if (targetItemIndex + growByCount > capacity)
-					{
-						capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, targetItemIndex, checked((int)BitOperations.RoundUpToPowerOf2((uint)(targetItemIndex + growByCount))));
-						memorySpan = new(_memoryBlock);
-						available = capacity - targetItemIndex;
-					}
-
-					for (i = 0; i < available; i++)
-					{
-						memorySpan[targetItemIndex++] = enumerator.Current;
-						if (!enumerator.MoveNext())
-						{
-							break;
-						}
-					}
-				}
-				while (i >= available);
-			}
-
-			_capacity = capacity;
-			_count = targetItemIndex;
-		}
-
-		private void AddRangeWithKnownCount(IEnumerable<T> items, int currentItemsCount, int requiredAdditionalCapacity)
-		{
-			_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, currentItemsCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)(currentItemsCount + requiredAdditionalCapacity))));
-
-			Span<T> memorySpan = new(_memoryBlock);
-			foreach (var item in items)
-			{
-				memorySpan[currentItemsCount++] = item;
-			}
-
-			_count = currentItemsCount;
-		}
-
 		public RecyclableList()
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
@@ -92,84 +41,67 @@ namespace Recyclable.Collections
 			}
 		}
 
-		public void AddRange(IReadOnlyList<T> items)
-		{
-			int sourceItemsCount = items.Count;
-			if (_capacity < _count + sourceItemsCount)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + sourceItemsCount))));
-			}
-
-			Span<T> memorySpan = new(_memoryBlock, _count, sourceItemsCount);
-			for (var sourceItemIndex = 0; sourceItemIndex < sourceItemsCount; sourceItemIndex++)
-			{
-				memorySpan[sourceItemIndex] = items[sourceItemIndex];
-			}
-
-			_count += sourceItemsCount;
-		}
-
 		public RecyclableList(in Array source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(RecyclableList<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(RecyclableLongList<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(ReadOnlySpan<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(in T[] source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(IReadOnlyList<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(List<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(ICollection source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(ICollection<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(IEnumerable source, int initialCapacity = RecyclableDefaults.InitialCapacity)
@@ -187,7 +119,7 @@ namespace Recyclable.Collections
 				_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
 			}
 
-			AddRange(source, RecyclableDefaults.MinPooledArrayLength);
+			zRecyclableListAddRange.AddRange(this, source, RecyclableDefaults.MinPooledArrayLength);
 		}
 
 		public RecyclableList(IEnumerable<T> source, int initialCapacity = RecyclableDefaults.InitialCapacity)
@@ -205,14 +137,14 @@ namespace Recyclable.Collections
 				_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
 			}
 
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableList(Span<T> source)
 		{
 			_capacity = RecyclableDefaults.InitialCapacity;
 			_memoryBlock = new T[RecyclableDefaults.InitialCapacity];
-			AddRange(source);
+			zRecyclableListAddRange.AddRange(this, source);
 		}
 
 		public T this[int index]
@@ -259,247 +191,6 @@ namespace Recyclable.Collections
 			_version++;
 		}
 
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(in Array items)
-		{
-			if (_capacity < _count + items.Length)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Length))));
-			}
-
-			Array.Copy(items, items.GetLowerBound(0), _memoryBlock, _count, items.LongLength);
-			_count += items.Length;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(in T[] items)
-		{
-			if (_capacity < _count + items.Length)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Length))));
-			}
-
-			new Span<T>(items).CopyTo(new Span<T>(_memoryBlock, _count, items.Length));
-			_count += items.Length;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(ReadOnlySpan<T> items)
-		{
-			if (_capacity < _count + items.Length)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Length))));
-			}
-
-			items.CopyTo(new Span<T>(_memoryBlock, _count, items.Length));
-			_count += items.Length;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(Span<T> items)
-		{
-			if (_capacity < _count + items.Length)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Length))));
-			}
-
-			items.CopyTo(new Span<T>(_memoryBlock, _count, items.Length));
-			_count += items.Length;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(List<T> items)
-		{
-			if (_capacity < _count + items.Count)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Count))));
-			}
-
-			items.CopyTo(_memoryBlock, _count);
-			_count += items.Count;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(ICollection items)
-		{
-			if (_capacity < _count + items.Count)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Count))));
-			}
-
-			items.CopyTo(_memoryBlock, _count);
-			_count += items.Count;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(ICollection<T> items)
-		{
-			if (_capacity < _count + items.Count)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items.Count))));
-			}
-
-			items.CopyTo(_memoryBlock, _count);
-			_count += items.Count;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(RecyclableList<T> items)
-		{
-			if (_capacity < _count + items._count)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, _count, checked((int)BitOperations.RoundUpToPowerOf2((uint)(_count + items._count))));
-			}
-
-			new Span<T>(items._memoryBlock, 0, items._count).CopyTo(new Span<T>(_memoryBlock, _count, items._count));
-			_count += items._count;
-			_version++;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(RecyclableLongList<T> items)
-		{
-			if (items._longCount == 0)
-			{
-				return;
-			}
-
-			int oldCount = _count;
-			long sourceItemsCount = items._longCount;
-			if (oldCount + sourceItemsCount > int.MaxValue)
-			{
-				ThrowHelper.ThrowArgumentOutOfRangeException(nameof(items), $"The total number of items in source and target table exceeds the maximum capacity of {nameof(RecyclableList<T>)}, equal {int.MaxValue}. Please consider using {nameof(RecyclableLongList<T>)}, instead");
-			}
-
-			int targetCapacity = oldCount + (int)sourceItemsCount;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
-			}
-
-			// TODO: Avoid unnecessary range operator - pass as arguments instead.
-			Span<T> targetSpan = new Span<T>(_memoryBlock)[oldCount..],
-				itemsSpan;
-
-			int blockIndex,
-				sourceBlockSize = items._blockSize,
-				lastBlockIndex = (int)(sourceItemsCount >> items._blockSizePow2BitShift) - 1;
-
-			for (blockIndex = 0; blockIndex <= lastBlockIndex; blockIndex++)
-			{
-				itemsSpan = new(items._memoryBlocks[blockIndex], 0, sourceBlockSize);
-				itemsSpan.CopyTo(targetSpan);
-				targetSpan = targetSpan[sourceBlockSize..];
-			}
-
-			if (blockIndex == 0)
-			{
-				itemsSpan = new(items._memoryBlocks[blockIndex], 0, (int)sourceItemsCount);
-				itemsSpan.CopyTo(targetSpan);
-			}
-			else if (blockIndex <= items._lastBlockWithData)
-			{
-				itemsSpan = new(items._memoryBlocks[blockIndex], 0, items._nextItemIndex);
-				itemsSpan.CopyTo(targetSpan);
-			}
-
-			_count = targetCapacity;
-			_version++;
-		}
-
-		public IEnumerator AddRange(IEnumerable source, int growByCount = RecyclableDefaults.MinPooledArrayLength)
-		{
-			int targetItemIndex = _count;
-			Span<T> memorySpan;
-
-			int i;
-			var enumerator = source.GetEnumerator();
-
-			int capacity = _capacity;
-			memorySpan = new(_memoryBlock);
-			if (enumerator.MoveNext())
-			{
-				int available = capacity - targetItemIndex;
-				do
-				{
-					if (targetItemIndex + growByCount > capacity)
-					{
-						capacity = RecyclableListHelpers<T>.ResizeAndCopy(this, targetItemIndex, checked((int)BitOperations.RoundUpToPowerOf2((uint)(targetItemIndex + growByCount))));
-						memorySpan = new(_memoryBlock);
-						available = capacity - targetItemIndex;
-					}
-
-					for (i = 0; i < available; i++)
-					{
-						memorySpan[targetItemIndex++] = (T)enumerator.Current;
-						if (!enumerator.MoveNext())
-						{
-							break;
-						}
-					}
-				}
-				while (i >= available);
-			}
-
-			_capacity = capacity;
-			_count = targetItemIndex;
-			return enumerator;
-		}
-
-		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public void AddRange(IEnumerable<T> items, int growByCount = RecyclableDefaults.MinPooledArrayLength)
-		{
-			if (items is RecyclableList<T> sourceRecyclableList)
-			{
-				AddRange(sourceRecyclableList);
-			}
-			else if (items is RecyclableLongList<T> sourceRecyclableLongList)
-			{
-				AddRange(sourceRecyclableLongList);
-			}
-			else if (items is T[] sourceArray)
-			{
-				AddRange(sourceArray);
-			}
-			else if (items is Array sourceArrayWithObjects)
-			{
-				AddRange(sourceArrayWithObjects);
-			}
-			else if (items is List<T> sourceList)
-			{
-				AddRange(sourceList);
-			}
-			else if (items is ICollection<T> sourceICollection)
-			{
-				AddRange(sourceICollection);
-			}
-			else if (items is ICollection sourceICollectionWithObjects)
-			{
-				AddRange(sourceICollectionWithObjects);
-			}
-			else if (items is IReadOnlyList<T> sourceIReadOnlyList)
-			{
-				AddRange(sourceIReadOnlyList);
-			}
-			else if (items.TryGetNonEnumeratedCount(out var requiredAdditionalCapacity) && requiredAdditionalCapacity != 0)
-			{
-				AddRangeWithKnownCount(items, _count, requiredAdditionalCapacity);
-				_version++;
-			}
-			else
-			{
-				AddRangeEnumerated(items, growByCount);
-				_version++;
-			}
-		}
-
 		public T[] AsArray => _memoryBlock;
 
 		[MethodImpl(MethodImplOptions.NoInlining)]
diff --git a/Recyclable.Collections/RecyclableLongList.AddRange.cs b/Recyclable.Collections/RecyclableLongList.AddRange.cs
new file mode 100644
index 0000000..dc96591
--- /dev/null
+++ b/Recyclable.Collections/RecyclableLongList.AddRange.cs
@@ -0,0 +1,819 @@
+using System.Collections;
+using System.Numerics;
+using Recyclable.Collections.Pools;
+
+namespace Recyclable.Collections
+{
+	public static class zRecyclableLongListAddRange
+	{
+		private static void AddRangeEnumerated<T>(this RecyclableLongList<T> targetList, IEnumerable<T> items)
+		{
+			using IEnumerator<T> enumerator = items.GetEnumerator();
+			if (!enumerator.MoveNext())
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				targetBlockIdx = targetList._nextItemBlockIndex,
+				targetItemIdx = targetList._nextItemIndex;
+
+			long capacity = targetList._capacity,
+				copied = targetList._longCount,
+				available = capacity - copied,
+				i;
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> blockArraySpan;
+
+			while (true)
+			{
+				if (copied + blockSize > capacity)
+				{
+					capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)(capacity + blockSize))));
+					memoryBlocksSpan = new(targetList._memoryBlocks);
+					available = capacity - copied;
+				}
+
+				blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+				for (i = 1; i <= available; i++)
+				{
+					blockArraySpan[targetItemIdx++] = enumerator.Current;
+
+					if (!enumerator.MoveNext())
+					{
+						targetList._lastBlockWithData = targetBlockIdx;
+						targetList._longCount += copied + i - targetList._longCount;
+						if (targetItemIdx < blockSize)
+						{
+							targetList._nextItemBlockIndex = targetBlockIdx;
+							targetList._nextItemIndex = targetItemIdx;
+						}
+						else
+						{
+							targetList._nextItemBlockIndex = targetBlockIdx + 1;
+							targetList._nextItemIndex = 0;
+						}
+
+						targetList._capacity = capacity;
+						targetList._version++;
+						return;
+					}
+
+					if (targetItemIdx == blockSize)
+					{
+						targetBlockIdx++;
+						targetItemIdx = 0;
+						if (i == available)
+						{
+							break;
+						}
+
+						blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+					}
+				}
+
+				copied += available;
+			}
+		}
+
+		private static void AddRangeWithKnownCount<T>(this RecyclableLongList<T> targetList, IEnumerable<T> items, int requiredAdditionalCapacity)
+		{
+			long requiredCapacity = targetList._longCount + requiredAdditionalCapacity;
+			if (requiredCapacity == 0)
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				targetBlockIdx = targetList._nextItemBlockIndex,
+				targetItemIdx = targetList._nextItemIndex;
+
+			if (targetList._capacity < requiredCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)requiredCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+			foreach (var item in items)
+			{
+				blockArraySpan[targetItemIdx++] = item;
+				if (targetItemIdx == blockSize)
+				{
+					targetBlockIdx++;
+					targetItemIdx = 0;
+					if (targetBlockIdx == memoryBlocksSpan.Length)
+					{
+						break;
+					}
+
+					blockArraySpan = new Span<T>(memoryBlocksSpan[targetBlockIdx]);
+				}
+			}
+
+			targetList._longCount = requiredCapacity;
+			targetList._nextItemBlockIndex = targetBlockIdx;
+			targetList._nextItemIndex = targetItemIdx;
+			targetList._lastBlockWithData = targetBlockIdx - (targetItemIdx > 0 ? 0 : 1);
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, in Array items)
+		{
+			if (items.LongLength == 0)
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long fullBlockItemsCount = items.LongLength - blockSize,
+				sourceItemIndex = Math.Min(blockSize - targetList._nextItemIndex, items.LongLength),
+				targetCapacity = targetList._longCount + items.LongLength;
+
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Array.Copy(items, 0, memoryBlocksSpan[targetBlockIndex++], targetList._nextItemIndex, sourceItemIndex);
+			while (sourceItemIndex < fullBlockItemsCount)
+			{
+				Array.Copy(items, sourceItemIndex, memoryBlocksSpan[targetBlockIndex++], 0, blockSize);
+				sourceItemIndex += blockSize;
+			}
+
+			// We're reusing a variable which is no longer needed. That's to avoid unnecessary
+			// allocation.
+			if ((blockSize = (int)(items.LongLength - sourceItemIndex)) > 0)
+			{
+				Array.Copy(items, sourceItemIndex, memoryBlocksSpan[targetBlockIndex], 0, blockSize);
+				targetList._lastBlockWithData = targetBlockIndex;
+				targetList._nextItemBlockIndex = targetBlockIndex;
+				targetList._nextItemIndex = blockSize;
+			}
+			else
+			{
+				targetList._lastBlockWithData = targetBlockIndex - 1;
+				if (targetList._nextItemIndex + sourceItemIndex >= targetList._blockSize)
+				{
+					targetList._nextItemBlockIndex = targetBlockIndex;
+					targetList._nextItemIndex = 0;
+				}
+				else
+				{
+					targetList._nextItemIndex += (int)sourceItemIndex;
+				}
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, ICollection items)
+		{
+			if (items.Count == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+			long targetCapacity = targetList._longCount + items.Count;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			// We're better off to temporarily copy it to a fixed array,
+			// than copying them item by item. We may run into OOMs, though.
+			T[] itemsBuffer = items.Count >= RecyclableDefaults.MinPooledArrayLength ? RecyclableArrayPool<T>.RentShared((int)BitOperations.RoundUpToPowerOf2((uint)items.Count)) : new T[items.Count];
+			items.CopyTo(itemsBuffer, 0);
+
+			Span<T> itemsSpan = new(itemsBuffer, 0, items.Count);
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+			while (targetBlockArraySpan.Length <= itemsSpan.Length)
+			{
+				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
+				targetBlockIndex++;
+				if (itemsSpan.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (itemsSpan.Length > 0)
+			{
+				itemsSpan.CopyTo(targetBlockArraySpan);
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = itemsSpan.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += itemsSpan.Length;
+				}
+			}
+			else
+			{
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._nextItemBlockIndex = targetBlockIndex;
+			targetList._lastBlockWithData = targetBlockIndex - (itemsSpan.Length > 0 ? 0 : 1);
+
+			if (items.Count >= RecyclableDefaults.MinPooledArrayLength)
+			{
+				RecyclableArrayPool<T>.ReturnShared(itemsBuffer, RecyclableLongList<T>._needsClearing);
+			}
+
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, ICollection<T> items)
+		{
+			if (items.Count == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long targetCapacity = targetList._longCount + items.Count;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			// We're better off to temporarily copy it to a fixed array,
+			// than copying them item by item. We may run into OOMs, though.
+			T[] itemsBuffer = items.Count >= RecyclableDefaults.MinPooledArrayLength ? RecyclableArrayPool<T>.RentShared((int)BitOperations.RoundUpToPowerOf2((uint)items.Count)) : new T[items.Count];
+
+			items.CopyTo(itemsBuffer, 0);
+
+			Span<T> itemsSpan = new(itemsBuffer, 0, items.Count);
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+				
+			while (targetBlockArraySpan.Length <= itemsSpan.Length)
+			{
+				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
+				targetBlockIndex++;
+				if (itemsSpan.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (itemsSpan.Length > 0)
+			{
+				itemsSpan.CopyTo(targetBlockArraySpan);
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = itemsSpan.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += itemsSpan.Length;
+				}
+			}
+			else
+			{
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._nextItemBlockIndex = targetBlockIndex;
+			targetList._lastBlockWithData = targetBlockIndex - (itemsSpan.Length > 0 ? 0 : 1);
+
+			if (items.Count >= RecyclableDefaults.MinPooledArrayLength)
+			{
+				RecyclableArrayPool<T>.ReturnShared(itemsBuffer, RecyclableLongList<T>._needsClearing);
+			}
+
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, IEnumerable source)
+		{
+			IEnumerator enumerator = source.GetEnumerator();
+			if (!enumerator.MoveNext())
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				targetBlockIdx = targetList._nextItemBlockIndex,
+				targetItemIdx = targetList._nextItemIndex;
+
+			long capacity = targetList._capacity,
+				copied = targetList._longCount,
+				available = capacity - copied,
+				i;
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> blockArraySpan;
+
+			while (true)
+			{
+				if (copied + blockSize > capacity)
+				{
+					capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)(capacity + blockSize))));
+					memoryBlocksSpan = new(targetList._memoryBlocks);
+					available = capacity - copied;
+				}
+
+				blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+				for (i = 1; i <= available; i++)
+				{
+					blockArraySpan[targetItemIdx++] = (T)enumerator.Current;
+
+					if (!enumerator.MoveNext())
+					{
+						targetList._lastBlockWithData = targetBlockIdx;
+						targetList._longCount += copied + i - targetList._longCount;
+						if (targetItemIdx < blockSize)
+						{
+							targetList._nextItemBlockIndex = targetBlockIdx;
+							targetList._nextItemIndex = targetItemIdx;
+						}
+						else
+						{
+							targetList._nextItemBlockIndex = targetBlockIdx + 1;
+							targetList._nextItemIndex = 0;
+						}
+
+						targetList._capacity = capacity;
+						return;
+					}
+
+					if (targetItemIdx == blockSize)
+					{
+						targetBlockIdx++;
+						targetItemIdx = 0;
+
+						if (i == available)
+						{
+							break;
+						}
+
+						blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+					}
+				}
+
+				copied += available;
+			}
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, IEnumerable<T> items)
+		{
+			switch (items)
+			{
+				case RecyclableList<T> sourceRecyclableList:
+					targetList.AddRange(sourceRecyclableList);
+					return;
+
+				case RecyclableLongList<T> sourceRecyclableLongList:
+					targetList.AddRange(sourceRecyclableLongList);
+					return;
+
+				case T[] sourceArray:
+					targetList.AddRange(sourceArray);
+					return;
+
+				case Array sourceArrayWithObjects:
+					targetList.AddRange(sourceArrayWithObjects);
+					return;
+
+				case List<T> sourceList:
+					targetList.AddRange(sourceList);
+					return;
+
+				case ICollection<T> sourceICollection:
+					targetList.AddRange(sourceICollection);
+					return;
+
+				case ICollection sourceICollectionWithObjects:
+					targetList.AddRange(sourceICollectionWithObjects);
+					return;
+
+				case IReadOnlyList<T> sourceIReadOnlyList:
+					targetList.AddRange(sourceIReadOnlyList);
+					return;
+
+				default:
+					if (items.TryGetNonEnumeratedCount(out var requiredAdditionalCapacity))
+					{
+						targetList.AddRangeWithKnownCount(items, requiredAdditionalCapacity);
+					}
+					else
+					{
+						targetList.AddRangeEnumerated(items);
+					}
+
+					return;
+			}
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, IReadOnlyList<T> items)
+		{
+			long sourceItemsCount = items.Count,
+				requiredCapacity = targetList._longCount + sourceItemsCount;
+
+			if (requiredCapacity == 0)
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				targetBlockIdx = targetList._nextItemBlockIndex,
+				targetItemIdx = targetList._nextItemIndex;
+
+			if (targetList._capacity < requiredCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)requiredCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
+
+			for (var itemIndex = 0; itemIndex < sourceItemsCount; itemIndex++)
+			{
+				blockArraySpan[targetItemIdx++] = items[itemIndex];
+				if (targetItemIdx == blockSize)
+				{
+					targetItemIdx = 0;
+					targetBlockIdx++;
+					if (itemIndex + 1 == sourceItemsCount)
+					{
+						break;
+					}
+
+					blockArraySpan = new Span<T>(memoryBlocksSpan[targetBlockIdx]);
+				}
+			}
+
+			targetList._longCount = requiredCapacity;
+			targetList._nextItemBlockIndex = targetBlockIdx;
+			targetList._nextItemIndex = targetItemIdx;
+			targetList._lastBlockWithData = targetBlockIdx - (targetItemIdx > 0 ? 0 : 1);
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, List<T> items)
+		{
+			if (items.Count == 0)
+			{
+				return;
+			}
+
+			int blockSize = targetList._blockSize,
+				itemsCount = items.Count,
+				copied = Math.Min(blockSize - targetList._nextItemIndex, itemsCount),
+				targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long targetCapacity = targetList._longCount + items.Count;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			items.CopyTo(0, memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, copied);
+
+			if (targetList._nextItemIndex + copied == blockSize)
+			{
+				targetBlockIndex++;
+				targetList._nextItemIndex = 0;
+			}
+			else
+			{
+				targetList._nextItemIndex += copied;
+			}
+
+			while (blockSize <= itemsCount - copied)
+			{
+				items.CopyTo(copied, memoryBlocksSpan[targetBlockIndex++], 0, blockSize);
+				copied += blockSize;
+			}
+
+			if ((itemsCount - copied < blockSize) && (itemsCount - copied != 0))
+			{
+				targetList._nextItemIndex = itemsCount - copied;
+				items.CopyTo(copied, memoryBlocksSpan[targetBlockIndex], 0, targetList._nextItemIndex);
+			}
+
+			targetList._nextItemBlockIndex = targetBlockIndex;
+			targetList._longCount = targetCapacity;
+			targetList._lastBlockWithData = targetBlockIndex - (targetList._nextItemIndex > 0 ? 0 : 1);
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, ReadOnlySpan<T> items)
+		{
+			if (items.Length == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long targetCapacity = targetList._longCount + items.Length;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+			
+			while (items.Length >= targetBlockArraySpan.Length)
+			{
+				items[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				items = items[targetBlockArraySpan.Length..];
+				if (items.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockIndex++;
+				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (items.Length > 0)
+			{
+				items.CopyTo(targetBlockArraySpan);
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = items.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += items.Length;
+				}
+			}
+			else
+			{
+				targetList._nextItemBlockIndex = targetBlockIndex + 1;
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._lastBlockWithData = targetBlockIndex;
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableList<T> items)
+		{
+			if (items._count == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long targetCapacity = targetList._longCount + items._count;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T> itemsSpan = new(items._memoryBlock, 0, items._count);
+			Span<T[]> targetMemoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+			
+			while (itemsSpan.Length >= targetBlockArraySpan.Length)
+			{
+				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
+				targetBlockIndex++;
+				if (itemsSpan.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (itemsSpan.Length > 0)
+			{
+				itemsSpan.CopyTo(targetBlockArraySpan);
+				targetList._lastBlockWithData = targetBlockIndex;
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = itemsSpan.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += itemsSpan.Length;
+				}
+			}
+			else
+			{
+				targetList._lastBlockWithData = targetBlockIndex - 1;
+				targetList._nextItemBlockIndex = targetBlockIndex;
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableLongList<T> items)
+		{
+			if (items._longCount == 0)
+			{
+				return;
+			}
+
+			int sourceBlockIndex = 0,
+				targetBlockIndex = targetList._nextItemBlockIndex,
+				toCopy;
+
+			long copiedCount = 0,
+				itemsCount = items._longCount,
+				targetCapacity = targetList._longCount + itemsCount;
+
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T[]> sourceMemoryBlocksSpan = new(items._memoryBlocks);
+			Span<T> itemsSpan = new(sourceMemoryBlocksSpan[sourceBlockIndex]);
+			Span<T[]> targetMemoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+			
+			while (copiedCount < itemsCount)
+			{
+				toCopy = checked((int)Math.Min(itemsCount - copiedCount, itemsSpan.Length));
+				if (targetBlockArraySpan.Length < toCopy)
+				{
+					toCopy = targetBlockArraySpan.Length;
+					itemsSpan[..toCopy].CopyTo(targetBlockArraySpan);
+					targetBlockIndex++;
+					targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
+					itemsSpan = itemsSpan[toCopy..];
+					copiedCount += toCopy;
+				}
+				else
+				{
+					itemsSpan[..toCopy].CopyTo(targetBlockArraySpan);
+					targetBlockArraySpan = targetBlockArraySpan[toCopy..];
+					itemsSpan = itemsSpan[toCopy..];
+					if (itemsSpan.IsEmpty && sourceBlockIndex + 1 < sourceMemoryBlocksSpan.Length)
+					{
+						sourceBlockIndex++;
+						itemsSpan = new(sourceMemoryBlocksSpan[sourceBlockIndex]);
+					}
+
+					copiedCount += toCopy;
+					if (targetBlockArraySpan.IsEmpty && copiedCount < itemsCount)
+					{
+						targetBlockIndex++;
+						targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
+					}
+				}
+			}
+
+			targetList._lastBlockWithData = targetBlockIndex;
+			if ((targetCapacity & targetList._blockSizeMinus1) == 0)
+			{
+				targetList._nextItemIndex = 0;
+				targetList._nextItemBlockIndex = targetBlockIndex + 1;
+			}
+			else
+			{
+				targetList._nextItemIndex = checked((int)(targetCapacity & targetList._blockSizeMinus1));
+				targetList._nextItemBlockIndex = targetBlockIndex;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, Span<T> items)
+		{
+			if (items.Length == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+			
+			long targetCapacity = targetList._longCount + items.Length;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+
+			while (items.Length >= targetBlockArraySpan.Length)
+			{
+				items[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				items = items[targetBlockArraySpan.Length..];
+				if (items.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockIndex++;
+				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (items.Length > 0)
+			{
+				items.CopyTo(targetBlockArraySpan);
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = items.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += items.Length;
+				}
+			}
+			else
+			{
+				targetList._nextItemBlockIndex = targetBlockIndex + 1;
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._lastBlockWithData = targetBlockIndex;
+			targetList._version++;
+		}
+
+		public static void AddRange<T>(this RecyclableLongList<T> targetList, in T[] items)
+		{
+			if (items.LongLength == 0)
+			{
+				return;
+			}
+
+			int targetBlockIndex = targetList._nextItemBlockIndex;
+
+			long targetCapacity = targetList._longCount + items.LongLength;
+			if (targetList._capacity < targetCapacity)
+			{
+				targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+			}
+
+			Span<T> itemsSpan = new(items);
+			Span<T[]> memoryBlocksSpan = new(targetList._memoryBlocks);
+			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], targetList._nextItemIndex, targetList._blockSize - targetList._nextItemIndex);
+
+			while (itemsSpan.Length >= targetBlockArraySpan.Length)
+			{
+				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
+				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
+				if (itemsSpan.Length == 0)
+				{
+					break;
+				}
+
+				targetBlockIndex++;
+				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
+			}
+
+			if (itemsSpan.Length > 0)
+			{
+				itemsSpan.CopyTo(targetBlockArraySpan);
+				if (targetList._nextItemBlockIndex != targetBlockIndex)
+				{
+					targetList._nextItemIndex = itemsSpan.Length;
+					targetList._nextItemBlockIndex = targetBlockIndex;
+				}
+				else
+				{
+					targetList._nextItemIndex += itemsSpan.Length;
+				}
+			}
+			else
+			{
+				targetList._nextItemBlockIndex = targetBlockIndex + 1;
+				targetList._nextItemIndex = 0;
+			}
+
+			targetList._longCount = targetCapacity;
+			targetList._lastBlockWithData = targetBlockIndex;
+			targetList._version++;
+		}
+	}
+}
diff --git a/Recyclable.Collections/RecyclableLongList.cs b/Recyclable.Collections/RecyclableLongList.cs
index 19add8e..bd23eb9 100644
--- a/Recyclable.Collections/RecyclableLongList.cs
+++ b/Recyclable.Collections/RecyclableLongList.cs
@@ -11,7 +11,7 @@ namespace Recyclable.Collections
 	public partial class RecyclableLongList<T> : IList<T>, IReadOnlyList<T>, IDisposable
 	{
 		private static readonly bool _defaultIsNull = default(T) == null;
-		private static readonly bool _needsClearing = !typeof(T).IsValueType;
+		internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
 		internal int _blockSize;
 		internal byte _blockSizePow2BitShift;
@@ -52,134 +52,17 @@ namespace Recyclable.Collections
 		public int NextItemIndex => _nextItemIndex;
 		public ulong Version => _version;
 
-		private void AddRangeEnumerated(IEnumerable<T> items)
-		{
-			using IEnumerator<T> enumerator = items.GetEnumerator();
-			if (!enumerator.MoveNext())
+		public RecyclableLongList(int minBlockSize = RecyclableDefaults.BlockSize, long initialCapacity = RecyclableDefaults.InitialCapacity)
+		{			
+			if (!BitOperations.IsPow2(minBlockSize))
 			{
-				return;
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
 			}
 
-			long i, copied = _longCount;
-			int blockSize = _blockSize,
-				targetItemIdx = _nextItemIndex,
-				targetBlockIdx = _nextItemBlockIndex;
-
-			long capacity = _capacity;
-			long available = capacity - copied;
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> blockArraySpan;
-
-			while (true)
-			{
-				if (copied + blockSize > capacity)
-				{
-					capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)(capacity + blockSize))));
-					memoryBlocksSpan = new(_memoryBlocks);
-					available = capacity - copied;
-				}
-
-				blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-				for (i = 1; i <= available; i++)
-				{
-					blockArraySpan[targetItemIdx++] = enumerator.Current;
-
-					if (!enumerator.MoveNext())
-					{
-						_lastBlockWithData = targetBlockIdx;
-						_longCount += copied + i - _longCount;
-						if (targetItemIdx < blockSize)
-						{
-							_nextItemBlockIndex = targetBlockIdx;
-							_nextItemIndex = targetItemIdx;
-						}
-						else
-						{
-							_nextItemBlockIndex = targetBlockIdx + 1;
-							_nextItemIndex = 0;
-						}
-
-						_capacity = capacity;
-						return;
-					}
-
-					if (targetItemIdx == blockSize)
-					{
-						targetBlockIdx++;
-						targetItemIdx = 0;
-						if (i == available)
-						{
-							break;
-						}
-
-						blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-					}
-				}
-
-				copied += available;
-			}
-		}
-
-		private void AddRangeWithKnownCount(IEnumerable<T> items, int requiredAdditionalCapacity)
-		{
-			long copied = _longCount;
-			int blockSize = _blockSize;
-			int targetItemIdx = _nextItemIndex;
-			int targetBlockIdx = _nextItemBlockIndex;
-
-			long requiredCapacity = copied + requiredAdditionalCapacity;
-			if (requiredCapacity == 0)
-			{
-				return;
-			}
-
-			if (_capacity < requiredCapacity)
-			{
-				_capacity = Helpers.Resize(this, blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)requiredCapacity)));
-				blockSize = _blockSize;
-			}
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-			foreach (var item in items)
-			{
-				blockArraySpan[targetItemIdx++] = item;
-				if (targetItemIdx == blockSize)
-				{
-					targetBlockIdx++;
-					targetItemIdx = 0;
-					if (targetBlockIdx == memoryBlocksSpan.Length)
-					{
-						break;
-					}
-
-					blockArraySpan = new Span<T>(memoryBlocksSpan[targetBlockIdx]);
-				}
-			}
-
-			_longCount = requiredCapacity;
-			_nextItemBlockIndex = targetBlockIdx;
-			_nextItemIndex = targetItemIdx;
-			_lastBlockWithData = targetBlockIdx - (targetItemIdx > 0 ? 0 : 1);
-		}
-
-		[MethodImpl(MethodImplOptions.AggressiveOptimization)]
-		public RecyclableLongList(int minBlockSize = RecyclableDefaults.BlockSize, long? initialCapacity = default)
-		{
-			minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
-
-			if (initialCapacity > 0)
-			{
-				Helpers.SetupBlockArrayPooling(this, minBlockSize);
-				_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)initialCapacity.Value)));
-				_blockSizeMinus1 = minBlockSize - 1;
-			}
-			else
-			{
-				Helpers.SetupBlockArrayPooling(this, minBlockSize);
-				_blockSizeMinus1 = _blockSize - 1;
-				_memoryBlocks = _emptyMemoryBlocksArray;
-			}
+			_blockSizePow2BitShift = (byte)(31 - BitOperations.LeadingZeroCount((uint)minBlockSize));
+			_capacity = RecyclableLongList<T>.Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)initialCapacity)));
+			_blockSize = minBlockSize;
+			_blockSizeMinus1 = minBlockSize - 1;
 		}
 
 		public RecyclableLongList(in T[] source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -190,7 +73,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)source.LongLength)));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(in Array source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -201,7 +84,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)source.LongLength)));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(IReadOnlyList<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -212,7 +95,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, BitOperations.RoundUpToPowerOf2((uint)source.Count));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(ReadOnlySpan<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -223,7 +106,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)source.Length)));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(RecyclableList<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -234,7 +117,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, BitOperations.RoundUpToPowerOf2((uint)source.Count));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(RecyclableLongList<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -245,7 +128,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)source.Count)));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(Span<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -256,7 +139,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)source.Length)));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(List<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -267,7 +150,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, BitOperations.RoundUpToPowerOf2((uint)source.Count));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(ICollection source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -278,7 +161,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, BitOperations.RoundUpToPowerOf2((uint)source.Count));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(ICollection<T> source, int minBlockSize = RecyclableDefaults.BlockSize)
@@ -289,7 +172,7 @@ namespace Recyclable.Collections
 			_capacity = Helpers.Resize(this, minBlockSize, _blockSizePow2BitShift, BitOperations.RoundUpToPowerOf2((uint)source.Count));
 			_blockSizeMinus1 = minBlockSize - 1;
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(IEnumerable source, int minBlockSize = RecyclableDefaults.BlockSize, long? initialCapacity = default)
@@ -306,7 +189,7 @@ namespace Recyclable.Collections
 				_memoryBlocks = _emptyMemoryBlocksArray;
 			}
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public RecyclableLongList(IEnumerable<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? initialCapacity = default)
@@ -323,7 +206,7 @@ namespace Recyclable.Collections
 				_memoryBlocks = _emptyMemoryBlocksArray;
 			}
 
-			AddRange(source);
+			zRecyclableLongListAddRange.AddRange(this, source);
 		}
 
 		public T this[long index]
@@ -376,710 +259,6 @@ namespace Recyclable.Collections
 			_version++;
 		}
 
-		public void AddRange(in Array items)
-		{
-			if (items.LongLength == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.LongLength;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			long fullBlockItemsCount = items.LongLength - blockSize,
-				 sourceItemIndex = Math.Min(blockSize - _nextItemIndex, items.LongLength);
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-
-			Array.Copy(items, 0, memoryBlocksSpan[targetBlockIndex++], _nextItemIndex, sourceItemIndex);
-			while (sourceItemIndex < fullBlockItemsCount)
-			{
-				Array.Copy(items, sourceItemIndex, memoryBlocksSpan[targetBlockIndex++], 0, blockSize);
-				sourceItemIndex += blockSize;
-			}
-
-			// We're reusing a variable which is no longer needed. That's to avoid unnecessary
-			// allocation.
-			if ((blockSize = (int)(items.LongLength - sourceItemIndex)) > 0)
-			{
-				Array.Copy(items, sourceItemIndex, memoryBlocksSpan[targetBlockIndex], 0, blockSize);
-				_lastBlockWithData = targetBlockIndex;
-				_nextItemBlockIndex = targetBlockIndex;
-				_nextItemIndex = blockSize;
-			}
-			else
-			{
-				_lastBlockWithData = targetBlockIndex - 1;
-				if (_nextItemIndex + sourceItemIndex >= _blockSize)
-				{
-					_nextItemBlockIndex = targetBlockIndex;
-					_nextItemIndex = 0;
-				}
-				else
-				{
-					_nextItemIndex += (int)sourceItemIndex;
-				}
-			}
-
-			_longCount = targetCapacity;
-			_version++;
-		}
-
-		public void AddRange(in T[] items)
-		{
-			if (items.LongLength == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.LongLength;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			Span<T> itemsSpan = new(items);
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-			while (itemsSpan.Length >= targetBlockArraySpan.Length)
-			{
-				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
-				if (itemsSpan.Length == 0)
-				{
-					break;
-				}
-
-				targetBlockIndex++;
-				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
-			}
-
-			if (itemsSpan.Length > 0)
-			{
-				itemsSpan.CopyTo(targetBlockArraySpan);
-				if (_nextItemBlockIndex != targetBlockIndex)
-				{
-					_nextItemIndex = itemsSpan.Length;
-					_nextItemBlockIndex = targetBlockIndex;
-				}
-				else
-				{
-					_nextItemIndex += itemsSpan.Length;
-				}
-			}
-			else
-			{
-				_nextItemBlockIndex = targetBlockIndex + 1;
-				_nextItemIndex = 0;
-			}
-
-			_longCount = targetCapacity;
-			_lastBlockWithData = targetBlockIndex;
-			_version++;
-		}
-
-		public void AddRange(RecyclableList<T> items)
-		{
-			if (items._count == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items._count;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			Span<T> itemsSpan = new(items._memoryBlock, 0, items._count);
-			Span<T[]> targetMemoryBlocksSpan = new(_memoryBlocks);
-			Span<T> targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-			while (itemsSpan.Length >= targetBlockArraySpan.Length)
-			{
-				itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-				itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
-				targetBlockIndex++;
-				if (itemsSpan.Length == 0)
-				{
-					break;
-				}
-
-				targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
-			}
-
-			if (itemsSpan.Length > 0)
-			{
-				itemsSpan.CopyTo(targetBlockArraySpan);
-				_lastBlockWithData = targetBlockIndex;
-				if (_nextItemBlockIndex != targetBlockIndex)
-				{
-					_nextItemIndex = itemsSpan.Length;
-					_nextItemBlockIndex = targetBlockIndex;
-				}
-				else
-				{
-					_nextItemIndex += itemsSpan.Length;
-				}
-			}
-			else
-			{
-				_lastBlockWithData = targetBlockIndex - 1;
-				_nextItemBlockIndex = targetBlockIndex;
-				_nextItemIndex = 0;
-			}
-
-			_longCount = targetCapacity;
-			_version++;
-		}
-
-		public void AddRange(ReadOnlySpan<T> items)
-		{
-			if (items.Length == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.Length;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-			while (items.Length >= targetBlockArraySpan.Length)
-			{
-				items[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-				items = items[targetBlockArraySpan.Length..];
-				if (items.Length == 0)
-				{
-					break;
-				}
-
-				targetBlockIndex++;
-				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
-			}
-
-			if (items.Length > 0)
-			{
-				items.CopyTo(targetBlockArraySpan);
-				if (_nextItemBlockIndex != targetBlockIndex)
-				{
-					_nextItemIndex = items.Length;
-					_nextItemBlockIndex = targetBlockIndex;
-				}
-				else
-				{
-					_nextItemIndex += items.Length;
-				}
-			}
-			else
-			{
-				_nextItemBlockIndex = targetBlockIndex + 1;
-				_nextItemIndex = 0;
-			}
-
-			_longCount = targetCapacity;
-			_lastBlockWithData = targetBlockIndex;
-			_version++;
-		}
-
-		public void AddRange(RecyclableLongList<T> items)
-		{
-			if (items._longCount == 0)
-			{
-				return;
-			}
-
-			long itemsCount = items._longCount,
-				targetCapacity = _longCount + itemsCount;
-
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				sourceBlockIndex = 0,
-				targetBlockIndex = _nextItemBlockIndex,
-				toCopy;
-
-			Span<T[]> sourceMemoryBlocksSpan = new(items._memoryBlocks);
-			Span<T> itemsSpan = new(sourceMemoryBlocksSpan[sourceBlockIndex]);
-			Span<T[]> targetMemoryBlocksSpan = new(_memoryBlocks);
-			Span<T> targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-			long copiedCount = 0;
-			while (copiedCount < itemsCount)
-			{
-				toCopy = checked((int)Math.Min(itemsCount - copiedCount, itemsSpan.Length));
-				if (targetBlockArraySpan.Length < toCopy)
-				{
-					toCopy = targetBlockArraySpan.Length;
-					itemsSpan[..toCopy].CopyTo(targetBlockArraySpan);
-					targetBlockIndex++;
-					targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
-					itemsSpan = itemsSpan[toCopy..];
-					copiedCount += toCopy;
-				}
-				else
-				{
-					itemsSpan[..toCopy].CopyTo(targetBlockArraySpan);
-					targetBlockArraySpan = targetBlockArraySpan[toCopy..];
-					itemsSpan = itemsSpan[toCopy..];
-					if (itemsSpan.IsEmpty && sourceBlockIndex + 1 < sourceMemoryBlocksSpan.Length)
-					{
-						sourceBlockIndex++;
-						itemsSpan = new(sourceMemoryBlocksSpan[sourceBlockIndex]);
-					}
-
-					copiedCount += toCopy;
-					if (targetBlockArraySpan.IsEmpty && copiedCount < itemsCount)
-					{
-						targetBlockIndex++;
-						targetBlockArraySpan = new(targetMemoryBlocksSpan[targetBlockIndex]);
-					}
-				}
-			}
-
-			_lastBlockWithData = targetBlockIndex;
-			if ((targetCapacity & _blockSizeMinus1) == 0)
-			{
-				_nextItemIndex = 0;
-				_nextItemBlockIndex = targetBlockIndex + 1;
-			}
-			else
-			{
-				_nextItemIndex = checked((int)(targetCapacity & _blockSizeMinus1));
-				_nextItemBlockIndex = targetBlockIndex;
-			}
-
-			_longCount = targetCapacity;
-			_version++;
-		}
-
-		public void AddRange(Span<T> items)
-		{
-			if (items.Length == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.Length;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-			while (items.Length >= targetBlockArraySpan.Length)
-			{
-				items[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-				items = items[targetBlockArraySpan.Length..];
-				if (items.Length == 0)
-				{
-					break;
-				}
-
-				targetBlockIndex++;
-				targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
-			}
-
-			if (items.Length > 0)
-			{
-				items.CopyTo(targetBlockArraySpan);
-				if (_nextItemBlockIndex != targetBlockIndex)
-				{
-					_nextItemIndex = items.Length;
-					_nextItemBlockIndex = targetBlockIndex;
-				}
-				else
-				{
-					_nextItemIndex += items.Length;
-				}
-			}
-			else
-			{
-				_nextItemBlockIndex = targetBlockIndex + 1;
-				_nextItemIndex = 0;
-			}
-
-			_longCount = targetCapacity;
-			_lastBlockWithData = targetBlockIndex;
-			_version++;
-		}
-
-		public void AddRange(List<T> items)
-		{
-			if (items.Count == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.Count;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex,
-				itemsCount = items.Count,
-				copied = Math.Min(blockSize - _nextItemIndex, itemsCount);
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			items.CopyTo(0, memoryBlocksSpan[targetBlockIndex], _nextItemIndex, copied);
-			if (_nextItemIndex + copied == blockSize)
-			{
-				targetBlockIndex++;
-				_nextItemIndex = 0;
-			}
-			else
-			{
-				_nextItemIndex += copied;
-			}
-
-			while (blockSize <= itemsCount - copied)
-			{
-				items.CopyTo(copied, memoryBlocksSpan[targetBlockIndex++], 0, blockSize);
-				copied += blockSize;
-			}
-
-			if ((itemsCount - copied < blockSize) && (itemsCount - copied != 0))
-			{
-				_nextItemIndex = itemsCount - copied;
-				items.CopyTo(copied, memoryBlocksSpan[targetBlockIndex], 0, _nextItemIndex);
-			}
-
-			_nextItemBlockIndex = targetBlockIndex;
-			_longCount = targetCapacity;
-			_lastBlockWithData = targetBlockIndex - (_nextItemIndex > 0 ? 0 : 1);
-			_version++;
-		}
-
-		public void AddRange(ICollection items)
-		{
-			if (items.Count == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.Count;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			// We're better off to temporarily copy it to a fixed array,
-			// than copying them item by item. We may run into OOMs, though.
-			T[] itemsBuffer = items.Count >= RecyclableDefaults.MinPooledArrayLength ? RecyclableArrayPool<T>.RentShared((int)BitOperations.RoundUpToPowerOf2((uint)items.Count)) : new T[items.Count];
-			try
-			{
-				items.CopyTo(itemsBuffer, 0);
-
-				Span<T> itemsSpan = new(itemsBuffer, 0, items.Count);
-				Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-				Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-				while (targetBlockArraySpan.Length <= itemsSpan.Length)
-				{
-					itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-					itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
-					targetBlockIndex++;
-					if (itemsSpan.Length == 0)
-					{
-						break;
-					}
-
-					targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
-				}
-
-				if (itemsSpan.Length > 0)
-				{
-					itemsSpan.CopyTo(targetBlockArraySpan);
-					if (_nextItemBlockIndex != targetBlockIndex)
-					{
-						_nextItemIndex = itemsSpan.Length;
-						_nextItemBlockIndex = targetBlockIndex;
-					}
-					else
-					{
-						_nextItemIndex += itemsSpan.Length;
-					}
-				}
-				else
-				{
-					_nextItemIndex = 0;
-				}
-
-				_longCount = targetCapacity;
-				_nextItemBlockIndex = targetBlockIndex;
-				_lastBlockWithData = targetBlockIndex - (itemsSpan.Length > 0 ? 0 : 1);
-			}
-			finally
-			{
-				if (items.Count >= RecyclableDefaults.MinPooledArrayLength)
-				{
-					RecyclableArrayPool<T>.ReturnShared(itemsBuffer, _needsClearing);
-				}
-
-				_version++;
-			}
-		}
-
-		public void AddRange(ICollection<T> items)
-		{
-			if (items.Count == 0)
-			{
-				return;
-			}
-
-			long targetCapacity = _longCount + items.Count;
-			if (_capacity < targetCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
-			}
-
-			int blockSize = _blockSize,
-				targetBlockIndex = _nextItemBlockIndex;
-
-			// We're better off to temporarily copy it to a fixed array,
-			// than copying them item by item. We may run into OOMs, though.
-			T[] itemsBuffer = items.Count >= RecyclableDefaults.MinPooledArrayLength ? RecyclableArrayPool<T>.RentShared((int)BitOperations.RoundUpToPowerOf2((uint)items.Count)) : new T[items.Count];
-			try
-			{
-				items.CopyTo(itemsBuffer, 0);
-
-				Span<T> itemsSpan = new(itemsBuffer, 0, items.Count);
-				Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-				Span<T> targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex], _nextItemIndex, blockSize - _nextItemIndex);
-				while (targetBlockArraySpan.Length <= itemsSpan.Length)
-				{
-					itemsSpan[..targetBlockArraySpan.Length].CopyTo(targetBlockArraySpan);
-					itemsSpan = itemsSpan[targetBlockArraySpan.Length..];
-					targetBlockIndex++;
-					if (itemsSpan.Length == 0)
-					{
-						break;
-					}
-
-					targetBlockArraySpan = new(memoryBlocksSpan[targetBlockIndex]);
-				}
-
-				if (itemsSpan.Length > 0)
-				{
-					itemsSpan.CopyTo(targetBlockArraySpan);
-					if (_nextItemBlockIndex != targetBlockIndex)
-					{
-						_nextItemIndex = itemsSpan.Length;
-						_nextItemBlockIndex = targetBlockIndex;
-					}
-					else
-					{
-						_nextItemIndex += itemsSpan.Length;
-					}
-				}
-				else
-				{
-					_nextItemIndex = 0;
-				}
-
-				_longCount = targetCapacity;
-				_nextItemBlockIndex = targetBlockIndex;
-				_lastBlockWithData = targetBlockIndex - (itemsSpan.Length > 0 ? 0 : 1);
-			}
-			finally
-			{
-				if (items.Count >= RecyclableDefaults.MinPooledArrayLength)
-				{
-					RecyclableArrayPool<T>.ReturnShared(itemsBuffer, _needsClearing);
-				}
-
-				_version++;
-			}
-		}
-
-		public void AddRange(IEnumerable source)
-		{
-			long i, copied = _longCount;
-			int blockSize = _blockSize,
-				targetItemIdx = _nextItemIndex,
-				targetBlockIdx = _nextItemBlockIndex;
-
-			IEnumerator enumerator = source.GetEnumerator();
-			if (!enumerator.MoveNext())
-			{
-				return;
-			}
-
-			long capacity = _capacity;
-			long available = capacity - copied;
-
-			Span<T[]> memoryBlocksSpan = new(_memoryBlocks);
-			Span<T> blockArraySpan;
-			while (true)
-			{
-				if (copied + blockSize > capacity)
-				{
-					capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)(capacity + blockSize))));
-					memoryBlocksSpan = new(_memoryBlocks);
-					available = capacity - copied;
-				}
-
-				blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-				for (i = 1; i <= available; i++)
-				{
-					blockArraySpan[targetItemIdx++] = (T)enumerator.Current;
-
-					if (!enumerator.MoveNext())
-					{
-						_lastBlockWithData = targetBlockIdx;
-						_longCount += copied + i - _longCount;
-						if (targetItemIdx < blockSize)
-						{
-							_nextItemBlockIndex = targetBlockIdx;
-							_nextItemIndex = targetItemIdx;
-						}
-						else
-						{
-							_nextItemBlockIndex = targetBlockIdx + 1;
-							_nextItemIndex = 0;
-						}
-
-						_capacity = capacity;
-						return;
-					}
-
-					if (targetItemIdx == blockSize)
-					{
-						targetBlockIdx++;
-						targetItemIdx = 0;
-
-						if (i == available)
-						{
-							break;
-						}
-
-						blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-					}
-				}
-
-				copied += available;
-			}
-		}
-
-		public void AddRange(IEnumerable<T> items)
-		{
-			if (items is RecyclableList<T> sourceRecyclableList)
-			{
-				AddRange(sourceRecyclableList);
-			}
-			else if (items is RecyclableLongList<T> sourceRecyclableLongList)
-			{
-				AddRange(sourceRecyclableLongList);
-			}
-			else if (items is T[] sourceArray)
-			{
-				AddRange(sourceArray);
-			}
-			else if (items is Array sourceArrayWithObjects)
-			{
-				AddRange(sourceArrayWithObjects);
-			}
-			else if (items is List<T> sourceList)
-			{
-				AddRange(sourceList);
-			}
-			else if (items is ICollection<T> sourceICollection)
-			{
-				AddRange(sourceICollection);
-			}
-			else if (items is ICollection sourceICollectionWithObjects)
-			{
-				AddRange(sourceICollectionWithObjects);
-			}
-			else if (items is IReadOnlyList<T> sourceIReadOnlyList)
-			{
-				AddRange(sourceIReadOnlyList);
-			}
-			else if (items.TryGetNonEnumeratedCount(out var requiredAdditionalCapacity))
-			{
-				AddRangeWithKnownCount(items, requiredAdditionalCapacity);
-				_version++;
-			}
-			else
-			{
-				AddRangeEnumerated(items);
-				_version++;
-			}
-		}
-
-		public void AddRange(IReadOnlyList<T> items)
-		{
-			long copied = _longCount;
-			int blockSize = _blockSize;
-			int targetItemIdx = _nextItemIndex;
-			int targetBlockIdx = _nextItemBlockIndex;
-
-			Span<T[]> memoryBlocksSpan;
-			Span<T> blockArraySpan;
-			long sourceItemsCount = items.Count;
-			long requiredCapacity = copied + sourceItemsCount;
-			if (requiredCapacity == 0)
-			{
-				return;
-			}
-
-			if (_capacity < requiredCapacity)
-			{
-				_capacity = Helpers.Resize(this, _blockSize, _blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)requiredCapacity)));
-				blockSize = _blockSize;
-			}
-
-			memoryBlocksSpan = new(_memoryBlocks);
-			blockArraySpan = new(memoryBlocksSpan[targetBlockIdx]);
-			for(var itemIndex = 0; itemIndex < sourceItemsCount; itemIndex++)
-			{
-				blockArraySpan[targetItemIdx++] = items[itemIndex];
-				if (targetItemIdx == blockSize)
-				{
-					targetItemIdx = 0;
-					targetBlockIdx++;
-					if (itemIndex + 1 == sourceItemsCount)
-					{
-						break;
-					}
-
-					blockArraySpan = new Span<T>(memoryBlocksSpan[targetBlockIdx]);
-				}
-			}
-
-			_longCount = requiredCapacity;
-			_nextItemBlockIndex = targetBlockIdx;
-			_nextItemIndex = targetItemIdx;
-			_lastBlockWithData = targetBlockIdx - (targetItemIdx > 0 ? 0 : 1);
-		}
-
 		public void Clear()
 		{
 			if (_longCount == 0)
@@ -1105,7 +284,6 @@ namespace Recyclable.Collections
 				}
 			}
 
-			// TODO: Do we want to initialize with empty arrays or null refs? Null refs may be faster.
 			Array.Fill(_memoryBlocks, null);
 			_capacity = 0;
 			_nextItemBlockIndex = 0;