diff --git a/Recyclable.Collections/RecyclableDictionary.cs b/Recyclable.Collections/RecyclableDictionary.cs
index c8da1e3..33cb849 100644
--- a/Recyclable.Collections/RecyclableDictionary.cs
+++ b/Recyclable.Collections/RecyclableDictionary.cs
@@ -9,20 +9,20 @@ namespace Recyclable.Collections
     internal sealed class RecyclableDictionary<TKey, TValue> : IEnumerable<KeyValuePair<TKey, TValue>>, IDisposable
         where TKey : notnull
     {
-        private static readonly bool _needsClearing = !typeof(TKey).IsValueType || !typeof(TValue).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(TKey).IsValueType || !typeof(TValue).IsValueType;
 
-        private readonly int _blockSize;
-        private readonly int _blockSizeMinus1;
-        private readonly byte _blockShift;
+        internal readonly int _blockSize;
+        internal readonly int _blockSizeMinus1;
+        internal readonly byte _blockShift;
 
 #nullable disable
-        private Entry[][] _entries;
+        internal Entry[][] _entries;
 #nullable restore
-        private int[] _buckets;
-        private int _count;
-        private bool _disposed;
+        internal int[] _buckets;
+        internal int _count;
+        internal bool _disposed;
 
-        private struct Entry
+        internal struct Entry
         {
             public int HashCode;
             public int Next;
diff --git a/Recyclable.Collections/RecyclableHashSet.cs b/Recyclable.Collections/RecyclableHashSet.cs
index 34ce553..2c532d0 100644
--- a/Recyclable.Collections/RecyclableHashSet.cs
+++ b/Recyclable.Collections/RecyclableHashSet.cs
@@ -9,20 +9,20 @@ namespace Recyclable.Collections
     internal sealed class RecyclableHashSet<T> : IEnumerable<T>, IDisposable
         where T : notnull
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
-        private readonly int _blockSize;
-        private readonly int _blockSizeMinus1;
-        private readonly byte _blockShift;
+        internal readonly int _blockSize;
+        internal readonly int _blockSizeMinus1;
+        internal readonly byte _blockShift;
 
 #nullable disable
-        private Entry[][] _entries;
+        internal Entry[][] _entries;
 #nullable restore
-        private int[] _buckets;
-        private int _count;
-        private bool _disposed;
+        internal int[] _buckets;
+        internal int _count;
+        internal bool _disposed;
 
-        private struct Entry
+        internal struct Entry
         {
             public int HashCode;
             public int Next;
diff --git a/Recyclable.Collections/RecyclableLinkedList.cs b/Recyclable.Collections/RecyclableLinkedList.cs
index b832de3..a0a95d0 100644
--- a/Recyclable.Collections/RecyclableLinkedList.cs
+++ b/Recyclable.Collections/RecyclableLinkedList.cs
@@ -7,7 +7,7 @@ namespace Recyclable.Collections
 {
     internal sealed class RecyclableLinkedList<T> : IEnumerable<T>, IDisposable
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static BiDirectionalRecyclableArrayPoolChunk<T> RentChunk(int size, BiDirectionalRecyclableArrayPoolChunk<T>? previous, bool forHead)
@@ -53,11 +53,11 @@ namespace Recyclable.Collections
             BiDirectionalRecyclableArrayPoolChunkPool<T>.Dispose(chunk, _needsClearing);
         }
 
-        private BiDirectionalRecyclableArrayPoolChunk<T> _head;
-        private BiDirectionalRecyclableArrayPoolChunk<T> _tail;
-        private bool _disposed;
-        private long _capacity;
-        private long _count;
+        internal BiDirectionalRecyclableArrayPoolChunk<T> _head;
+        internal BiDirectionalRecyclableArrayPoolChunk<T> _tail;
+        internal bool _disposed;
+        internal long _capacity;
+        internal long _count;
 
         public RecyclableLinkedList(int initialCapacity = RecyclableDefaults.InitialCapacity)
         {
diff --git a/Recyclable.Collections/RecyclableList.AddRange.cs b/Recyclable.Collections/RecyclableList.AddRange.cs
index 5aa15ee..87b00e3 100644
--- a/Recyclable.Collections/RecyclableList.AddRange.cs
+++ b/Recyclable.Collections/RecyclableList.AddRange.cs
@@ -162,12 +162,12 @@ namespace Recyclable.Collections
 		}
 
 		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
-		public static void AddRange<T>(this RecyclableList<T> list, RecyclableLongList<T> items)
-		{
-			if (items._longCount == 0)
-			{
-				return;
-			}
+                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;
@@ -208,9 +208,263 @@ namespace Recyclable.Collections
 				itemsSpan.CopyTo(targetSpan);
 			}
 
-			list._count = targetCapacity;
-			list._version++;
-		}
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclableHashSet<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = items._count,
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<T> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        var entries = items._entries;
+                        int shift = items._blockShift,
+                                mask = items._blockSizeMinus1;
+
+                        for (int i = 0; i < sourceCount; i++)
+                        {
+                                targetSpan[i] = entries[i >> shift][i & mask].Value;
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclableStack<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        if (items._count > int.MaxValue - list._count)
+                        {
+                                ThrowHelper.ThrowArgumentOutOfRangeException(nameof(items), "The total number of items exceeds the capacity of RecyclableList.");
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = checked((int)items._count),
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<T> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        int index = 0;
+                        var chunk = items._current;
+                        while (chunk != null)
+                        {
+                                var array = chunk.Value;
+                                for (int i = chunk.Index - 1; i >= 0; i--)
+                                {
+                                        targetSpan[index++] = array[i];
+                                }
+
+                                chunk = chunk.Previous;
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclableSortedSet<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = items._count,
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        new ReadOnlySpan<T>(items._items, 0, sourceCount).CopyTo(new Span<T>(list._memoryBlock, oldCount, sourceCount));
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclableLinkedList<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        if (items._count > int.MaxValue - list._count)
+                        {
+                                ThrowHelper.ThrowArgumentOutOfRangeException(nameof(items), "The total number of items exceeds the capacity of RecyclableList.");
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = checked((int)items._count),
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<T> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        int index = 0;
+                        var chunk = items._head;
+                        while (chunk != null)
+                        {
+                                for (int i = chunk.Bottom; i < chunk.Top; i++)
+                                {
+                                        targetSpan[index++] = chunk.Value[i];
+                                }
+
+                                chunk = chunk.Next;
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclablePriorityQueue<T> items)
+                {
+                        if (items._size == 0)
+                        {
+                                return;
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = items._size,
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        new ReadOnlySpan<T>(items._heap, 0, sourceCount).CopyTo(new Span<T>(list._memoryBlock, oldCount, sourceCount));
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableList<T> list, RecyclableQueue<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        if (items._count > int.MaxValue - list._count)
+                        {
+                                ThrowHelper.ThrowArgumentOutOfRangeException(nameof(items), "The total number of items exceeds the capacity of RecyclableList.");
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = checked((int)items._count),
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<T>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<T> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        int index = 0;
+                        var chunk = items._head;
+                        while (chunk != null)
+                        {
+                                for (int i = chunk.Bottom; i < chunk.Top; i++)
+                                {
+                                        targetSpan[index++] = chunk.Value[i];
+                                }
+
+                                chunk = chunk.Next;
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<TKey, TValue>(this RecyclableList<KeyValuePair<TKey, TValue>> list, RecyclableDictionary<TKey, TValue> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = items._count,
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<KeyValuePair<TKey, TValue>>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<KeyValuePair<TKey, TValue>> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        var entries = items._entries;
+                        int shift = items._blockShift,
+                                mask = items._blockSizeMinus1;
+
+                        for (int i = 0; i < sourceCount; i++)
+                        {
+                                ref var entry = ref entries[i >> shift][i & mask];
+                                targetSpan[i] = new KeyValuePair<TKey, TValue>(entry.Key, entry.Value);
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<TKey, TValue>(this RecyclableList<(TKey Key, TValue Value)> list, RecyclableSortedList<TKey, TValue> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        int oldCount = list._count,
+                                sourceCount = items._count,
+                                targetCapacity = oldCount + sourceCount;
+
+                        if (list._capacity < targetCapacity)
+                        {
+                                list._capacity = RecyclableListHelpers<(TKey Key, TValue Value)>.EnsureCapacity(list, oldCount, checked((int)BitOperations.RoundUpToPowerOf2((uint)targetCapacity)));
+                        }
+
+                        Span<(TKey Key, TValue Value)> targetSpan = new(list._memoryBlock, oldCount, sourceCount);
+                        for (int i = 0; i < sourceCount; i++)
+                        {
+                                targetSpan[i] = (items._keys[i], items._values[i]);
+                        }
+
+                        list._count = targetCapacity;
+                        list._version++;
+                }
 
 		public static IEnumerator AddRange<T>(this RecyclableList<T> list, IEnumerable source, int growByCount = RecyclableDefaults.MinPooledArrayLength)
 		{
@@ -291,15 +545,39 @@ namespace Recyclable.Collections
 			{
 				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)
+                        else if (items is ICollection<T> sourceICollection)
+                        {
+                                AddRange(list, sourceICollection);
+                        }
+                        else if (items is ICollection sourceICollectionWithObjects)
+                        {
+                                AddRange(list, sourceICollectionWithObjects);
+                        }
+                        else if (items is RecyclableHashSet<T> sourceHashSet)
+                        {
+                                AddRange(list, sourceHashSet);
+                        }
+                        else if (items is RecyclableStack<T> sourceStack)
+                        {
+                                AddRange(list, sourceStack);
+                        }
+                        else if (items is RecyclableSortedSet<T> sourceSortedSet)
+                        {
+                                AddRange(list, sourceSortedSet);
+                        }
+                        else if (items is RecyclableLinkedList<T> sourceLinkedList)
+                        {
+                                AddRange(list, sourceLinkedList);
+                        }
+                        else if (items is RecyclablePriorityQueue<T> sourcePriorityQueue)
+                        {
+                                AddRange(list, sourcePriorityQueue);
+                        }
+                        else if (items is RecyclableQueue<T> sourceQueue)
+                        {
+                                AddRange(list, sourceQueue);
+                        }
+                        else if (items is IReadOnlyList<T> sourceIReadOnlyList)
 			{
 				AddRange(list, sourceIReadOnlyList);
 			}
diff --git a/Recyclable.Collections/RecyclableLongList.AddRange.cs b/Recyclable.Collections/RecyclableLongList.AddRange.cs
index e8f5b79..92dcef1 100644
--- a/Recyclable.Collections/RecyclableLongList.AddRange.cs
+++ b/Recyclable.Collections/RecyclableLongList.AddRange.cs
@@ -1,5 +1,6 @@
 using System.Collections;
 using System.Numerics;
+using System.Runtime.CompilerServices;
 using Recyclable.Collections.Pools;
 
 namespace Recyclable.Collections
@@ -405,13 +406,37 @@ namespace Recyclable.Collections
 					targetList.AddRange(sourceICollection);
 					return;
 
-				case ICollection sourceICollectionWithObjects:
-					targetList.AddRange(sourceICollectionWithObjects);
-					return;
+                                case ICollection sourceICollectionWithObjects:
+                                        targetList.AddRange(sourceICollectionWithObjects);
+                                        return;
 
-				case IReadOnlyList<T> sourceIReadOnlyList:
-					targetList.AddRange(sourceIReadOnlyList);
-					return;
+                                case IReadOnlyList<T> sourceIReadOnlyList:
+                                        targetList.AddRange(sourceIReadOnlyList);
+                                        return;
+
+                                case RecyclableHashSet<T> sourceHashSet:
+                                        targetList.AddRange(sourceHashSet);
+                                        return;
+
+                                case RecyclableStack<T> sourceStack:
+                                        targetList.AddRange(sourceStack);
+                                        return;
+
+                                case RecyclableSortedSet<T> sourceSortedSet:
+                                        targetList.AddRange(sourceSortedSet);
+                                        return;
+
+                                case RecyclableLinkedList<T> sourceLinkedList:
+                                        targetList.AddRange(sourceLinkedList);
+                                        return;
+
+                                case RecyclablePriorityQueue<T> sourcePriorityQueue:
+                                        targetList.AddRange(sourcePriorityQueue);
+                                        return;
+
+                                case RecyclableQueue<T> sourceQueue:
+                                        targetList.AddRange(sourceQueue);
+                                        return;
 
 				default:
 					if (items.TryGetNonEnumeratedCount(out var requiredAdditionalCapacity))
@@ -760,12 +785,12 @@ namespace Recyclable.Collections
 			targetList._version++;
 		}
 
-		public static void AddRange<T>(this RecyclableLongList<T> targetList, in T[] items)
-		{
-			if (items.LongLength == 0)
-			{
-				return;
-			}
+                public static void AddRange<T>(this RecyclableLongList<T> targetList, in T[] items)
+                {
+                        if (items.LongLength == 0)
+                        {
+                                return;
+                        }
 
 			int targetBlockIndex = targetList._nextItemBlockIndex;
 
@@ -812,8 +837,344 @@ namespace Recyclable.Collections
 			}
 
 			targetList._longCount = targetCapacity;
-			targetList._lastBlockWithData = targetBlockIndex;
-			targetList._version++;
-		}
+                        targetList._lastBlockWithData = targetBlockIndex;
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableHashSet<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        var entries = items._entries;
+                        int shift = items._blockShift,
+                                mask = items._blockSizeMinus1;
+
+                        for (long i = 0; i < sourceCount; i++)
+                        {
+                                blocks[blockIndex][itemIndex++] = entries[i >> shift][(int)(i & mask)].Value;
+                                if (itemIndex == blockSize)
+                                {
+                                        itemIndex = 0;
+                                        blockIndex++;
+                                }
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableStack<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        var chunk = items._current;
+                        while (chunk != null)
+                        {
+                                var array = chunk.Value;
+                                for (int i = chunk.Index - 1; i >= 0; i--)
+                                {
+                                        blocks[blockIndex][itemIndex++] = array[i];
+                                        if (itemIndex == blockSize)
+                                        {
+                                                itemIndex = 0;
+                                                blockIndex++;
+                                        }
+                                }
+
+                                chunk = chunk.Previous;
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableSortedSet<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        int idx = 0;
+                        while (idx < items._count)
+                        {
+                                blocks[blockIndex][itemIndex++] = items._items[idx++];
+                                if (itemIndex == blockSize)
+                                {
+                                        itemIndex = 0;
+                                        blockIndex++;
+                                }
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableLinkedList<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        var chunk = items._head;
+                        while (chunk != null)
+                        {
+                                for (int i = chunk.Bottom; i < chunk.Top; i++)
+                                {
+                                        blocks[blockIndex][itemIndex++] = chunk.Value[i];
+                                        if (itemIndex == blockSize)
+                                        {
+                                                itemIndex = 0;
+                                                blockIndex++;
+                                        }
+                                }
+
+                                chunk = chunk.Next;
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclablePriorityQueue<T> items)
+                {
+                        if (items._size == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._size,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        int idx = 0;
+                        while (idx < items._size)
+                        {
+                                blocks[blockIndex][itemIndex++] = items._heap[idx++];
+                                if (itemIndex == blockSize)
+                                {
+                                        itemIndex = 0;
+                                        blockIndex++;
+                                }
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<T>(this RecyclableLongList<T> targetList, RecyclableQueue<T> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<T>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        var chunkQ = items._head;
+                        while (chunkQ != null)
+                        {
+                                for (int i = chunkQ.Bottom; i < chunkQ.Top; i++)
+                                {
+                                        blocks[blockIndex][itemIndex++] = chunkQ.Value[i];
+                                        if (itemIndex == blockSize)
+                                        {
+                                                itemIndex = 0;
+                                                blockIndex++;
+                                        }
+                                }
+
+                                chunkQ = chunkQ.Next;
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<TKey, TValue>(this RecyclableLongList<KeyValuePair<TKey, TValue>> targetList, RecyclableDictionary<TKey, TValue> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<KeyValuePair<TKey, TValue>>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        var entries = items._entries;
+                        int shift = items._blockShift,
+                                mask = items._blockSizeMinus1;
+
+                        for (long i = 0; i < sourceCount; i++)
+                        {
+                                ref var entry = ref entries[i >> shift][(int)(i & mask)];
+                                blocks[blockIndex][itemIndex++] = new KeyValuePair<TKey, TValue>(entry.Key, entry.Value);
+                                if (itemIndex == blockSize)
+                                {
+                                        itemIndex = 0;
+                                        blockIndex++;
+                                }
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
+
+                [MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+                internal static void AddRange<TKey, TValue>(this RecyclableLongList<(TKey Key, TValue Value)> targetList, RecyclableSortedList<TKey, TValue> items)
+                {
+                        if (items._count == 0)
+                        {
+                                return;
+                        }
+
+                        long sourceCount = items._count,
+                                targetCapacity = targetList._longCount + sourceCount;
+
+                        if (targetList._capacity < targetCapacity)
+                        {
+                                targetList._capacity = RecyclableLongList<(TKey Key, TValue Value)>.Helpers.Resize(targetList, targetList._blockSize, targetList._blockSizePow2BitShift, checked((long)BitOperations.RoundUpToPowerOf2((ulong)targetCapacity)));
+                        }
+
+                        var blocks = targetList._memoryBlocks;
+                        int blockIndex = targetList._nextItemBlockIndex,
+                                itemIndex = targetList._nextItemIndex,
+                                blockSize = targetList._blockSize;
+
+                        int idx2 = 0;
+                        while (idx2 < items._count)
+                        {
+                                blocks[blockIndex][itemIndex++] = (items._keys[idx2], items._values[idx2]);
+                                idx2++;
+                                if (itemIndex == blockSize)
+                                {
+                                        itemIndex = 0;
+                                        blockIndex++;
+                                }
+                        }
+
+                        targetList._longCount = targetCapacity;
+                        targetList._nextItemBlockIndex = blockIndex;
+                        targetList._nextItemIndex = itemIndex;
+                        targetList._lastBlockWithData = blockIndex - (itemIndex > 0 ? 0 : 1);
+                        targetList._version++;
+                }
 	}
 }
diff --git a/Recyclable.Collections/RecyclablePriorityQueue.cs b/Recyclable.Collections/RecyclablePriorityQueue.cs
index c4fe439..ca80fab 100644
--- a/Recyclable.Collections/RecyclablePriorityQueue.cs
+++ b/Recyclable.Collections/RecyclablePriorityQueue.cs
@@ -7,15 +7,15 @@ namespace Recyclable.Collections
 {
     internal sealed class RecyclablePriorityQueue<T> : IEnumerable<T>, IDisposable
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
-        private readonly IComparer<T> _comparer;
+        internal readonly IComparer<T> _comparer;
 
 #nullable disable
-        private T[] _heap;
+        internal T[] _heap;
 #nullable restore
-        private int _size;
-        private bool _disposed;
+        internal int _size;
+        internal bool _disposed;
 
         public RecyclablePriorityQueue(int initialCapacity = RecyclableDefaults.InitialCapacity, IComparer<T>? comparer = null)
         {
diff --git a/Recyclable.Collections/RecyclableQueue.cs b/Recyclable.Collections/RecyclableQueue.cs
index 30dd59d..6f4c814 100644
--- a/Recyclable.Collections/RecyclableQueue.cs
+++ b/Recyclable.Collections/RecyclableQueue.cs
@@ -7,7 +7,7 @@ namespace Recyclable.Collections
 {
     internal sealed class RecyclableQueue<T> : IEnumerable<T>, IDisposable
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static BiDirectionalRecyclableArrayPoolChunk<T> RentChunk(int size, BiDirectionalRecyclableArrayPoolChunk<T>? previous)
@@ -44,11 +44,11 @@ namespace Recyclable.Collections
             BiDirectionalRecyclableArrayPoolChunkPool<T>.Dispose(chunk, _needsClearing);
         }
 
-        private BiDirectionalRecyclableArrayPoolChunk<T> _head;
-        private BiDirectionalRecyclableArrayPoolChunk<T> _tail;
-        private bool _disposed;
-        private long _capacity;
-        private long _count;
+        internal BiDirectionalRecyclableArrayPoolChunk<T> _head;
+        internal BiDirectionalRecyclableArrayPoolChunk<T> _tail;
+        internal bool _disposed;
+        internal long _capacity;
+        internal long _count;
 
         public RecyclableQueue(int initialCapacity = RecyclableDefaults.InitialCapacity)
         {
diff --git a/Recyclable.Collections/RecyclableSortedList.cs b/Recyclable.Collections/RecyclableSortedList.cs
index 9a7af04..9b371ea 100644
--- a/Recyclable.Collections/RecyclableSortedList.cs
+++ b/Recyclable.Collections/RecyclableSortedList.cs
@@ -8,13 +8,13 @@ namespace Recyclable.Collections
     internal sealed class RecyclableSortedList<TKey, TValue> : IEnumerable<(TKey Key, TValue Value)>, IDisposable
         where TKey : notnull
     {
-        private static readonly bool _needsClearing = !typeof(TKey).IsValueType || !typeof(TValue).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(TKey).IsValueType || !typeof(TValue).IsValueType;
 
-        private TKey[] _keys;
-        private TValue[] _values;
-        private int _count;
-        private readonly IComparer<TKey> _comparer;
-        private bool _disposed;
+        internal TKey[] _keys;
+        internal TValue[] _values;
+        internal int _count;
+        internal readonly IComparer<TKey> _comparer;
+        internal bool _disposed;
 
         public RecyclableSortedList(int initialCapacity = RecyclableDefaults.InitialCapacity, IComparer<TKey>? comparer = null)
         {
diff --git a/Recyclable.Collections/RecyclableSortedSet.cs b/Recyclable.Collections/RecyclableSortedSet.cs
index e5ad458..6c7db74 100644
--- a/Recyclable.Collections/RecyclableSortedSet.cs
+++ b/Recyclable.Collections/RecyclableSortedSet.cs
@@ -7,13 +7,13 @@ namespace Recyclable.Collections
 {
     internal sealed class RecyclableSortedSet<T> : IEnumerable<T>, IDisposable where T : notnull
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
-        private readonly IComparer<T> _comparer;
+        internal readonly IComparer<T> _comparer;
 
-        private T[] _items;
-        private int _count;
-        private bool _disposed;
+        internal T[] _items;
+        internal int _count;
+        internal bool _disposed;
 
         public RecyclableSortedSet(int initialCapacity = RecyclableDefaults.InitialCapacity, IComparer<T>? comparer = null)
         {
diff --git a/Recyclable.Collections/RecyclableStack.cs b/Recyclable.Collections/RecyclableStack.cs
index 27b9e04..e5bd8a2 100644
--- a/Recyclable.Collections/RecyclableStack.cs
+++ b/Recyclable.Collections/RecyclableStack.cs
@@ -7,7 +7,7 @@ namespace Recyclable.Collections
 {
     internal sealed class RecyclableStack<T> : IEnumerable<T>, IDisposable
     {
-        private static readonly bool _needsClearing = !typeof(T).IsValueType;
+        internal static readonly bool _needsClearing = !typeof(T).IsValueType;
 
         [MethodImpl(MethodImplOptions.AggressiveInlining)]
         private static RecyclableArrayPoolChunk<T> RentChunk(int size, RecyclableArrayPoolChunk<T>? previous)
@@ -42,10 +42,10 @@ namespace Recyclable.Collections
             RecyclableArrayPoolChunkPool<T>.Dispose(chunk, _needsClearing);
         }
 
-        private RecyclableArrayPoolChunk<T> _current;
-        private bool _disposed;
-        private long _capacity;
-        private long _count;
+        internal RecyclableArrayPoolChunk<T> _current;
+        internal bool _disposed;
+        internal long _capacity;
+        internal long _count;
 
         public RecyclableStack(int initialCapacity = RecyclableDefaults.InitialCapacity)
         {