diff --git a/Recyclable.Collections/RecyclableList.cs b/Recyclable.Collections/RecyclableList.cs
index 19937d3..bbc85bf 100644
--- a/Recyclable.Collections/RecyclableList.cs
+++ b/Recyclable.Collections/RecyclableList.cs
@@ -12,6 +12,8 @@ namespace Recyclable.Collections
 
 		protected T[] _memoryBlock;
 
+		public static explicit operator ReadOnlySpan<T>(RecyclableList<T> source) => new(source._memoryBlock, 0, source.Count);
+
 		private static void ThrowArgumentOutOfRangeException(in string message)
 		{
 			throw new ArgumentOutOfRangeException(message, (Exception?)null);
@@ -92,6 +94,20 @@ namespace Recyclable.Collections
 			AddRange(source);
 		}
 
+#pragma warning disable CS8618 // _memory will be initialized when the 1st item is added
+		public RecyclableList(RecyclableLongList<T> source)
+#pragma warning restore CS8618
+		{
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // _memory will be initialized when the 1st item is added
+		public RecyclableList(ReadOnlySpan<T> source)
+#pragma warning restore CS8618
+		{
+			AddRange(source);
+		}
+
 #pragma warning disable CS8618 // _memory will be initialized when the 1st item is added
 		public RecyclableList(in T[] source)
 #pragma warning restore CS8618
@@ -188,6 +204,26 @@ namespace Recyclable.Collections
 			_count = targetCapacity;
 		}
 
+		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
+		public void AddRange(ReadOnlySpan<T> itemsSpan)
+		{
+			if (itemsSpan.Length == 0)
+			{
+				return;
+			}
+
+			int sourceItemsCount = itemsSpan.Length;
+			int targetCapacity = _count + sourceItemsCount;
+			if (_capacity < targetCapacity)
+			{
+				_ = EnsureCapacity(this, targetCapacity);
+			}
+
+			var targetSpan = new Span<T>(_memoryBlock, _count, sourceItemsCount);
+			itemsSpan.CopyTo(targetSpan);
+			_count = targetCapacity;
+		}
+
 		[MethodImpl(MethodImplOptions.NoInlining | MethodImplOptions.AggressiveOptimization)]
 		public void AddRange(List<T> items)
 		{
diff --git a/Recyclable.Collections/RecyclableLongList.cs b/Recyclable.Collections/RecyclableLongList.cs
index e1ac32c..9394aa9 100644
--- a/Recyclable.Collections/RecyclableLongList.cs
+++ b/Recyclable.Collections/RecyclableLongList.cs
@@ -417,6 +417,186 @@ namespace Recyclable.Collections
 			}
 		}
 
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(in T[] source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(ReadOnlySpan<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(RecyclableList<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(RecyclableLongList<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(List<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
+#pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
+		public RecyclableLongList(IList<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
+#pragma warning restore CS8618
+		{
+			_memoryBlocksPool = memoryBlocksPool ?? _defaultMemoryBlocksPool;
+			if (expectedItemsCount > 0)
+			{
+				minBlockSize = checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize));
+				SetupBlockArrayPooling(this, minBlockSize, blockArrayPool);
+				_capacity = Resize(this, minBlockSize, _blockSizePow2BitShift, expectedItemsCount.Value);
+				if (minBlockSize != _memoryBlocks![0].Length && _capacity > 0)
+				{
+					SetupBlockArrayPooling(this, _memoryBlocks[0].Length, blockArrayPool);
+					_blockSizeMinus1 = _blockSize - 1;
+				}
+				else
+				{
+					_blockSizeMinus1 = minBlockSize - 1;
+				}
+			}
+			else
+			{
+				SetupBlockArrayPooling(this, checked((int)BitOperations.RoundUpToPowerOf2((uint)minBlockSize)), blockArrayPool);
+				_blockSizeMinus1 = _blockSize - 1;
+				_memoryBlocks = _emptyMemoryBlocksArray;
+			}
+
+			AddRange(source);
+		}
+
 #pragma warning disable CS8618 // It's set by SetupBlockArrayPooling
 		public RecyclableLongList(IEnumerable<T> source, int minBlockSize = RecyclableDefaults.BlockSize, long? expectedItemsCount = default, ArrayPool<T[]>? memoryBlocksPool = default, ArrayPool<T>? blockArrayPool = default)
 #pragma warning restore CS8618
@@ -576,6 +756,53 @@ namespace Recyclable.Collections
 			_lastBlockWithData = targetBlockIndex - (itemsSpan.Length > 0 ? 0 : 1);
 		}
 
+		public void AddRange(ReadOnlySpan<T> itemsSpan)
+		{
+			if (itemsSpan.Length == 0)
+			{
+				return;
+			}
+
+			long targetCapacity = _longCount + itemsSpan.Length;
+			if (_capacity < targetCapacity)
+			{
+				_ = EnsureCapacity(this, targetCapacity);
+			}
+
+			int blockSize = _blockSize,
+				targetBlockIndex = _nextItemBlockIndex,
+				memoryBlockCount = _reservedBlockCount;
+
+			Span<T[]> memoryBlocksSpan = new(_memoryBlocks, 0, memoryBlockCount);
+			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], 0, blockSize);
+			}
+
+			if (itemsSpan.Length > 0)
+			{
+				itemsSpan.CopyTo(targetBlockArraySpan);
+				_nextItemBlockIndex = targetBlockIndex;
+			}
+			else
+			{
+				_nextItemBlockIndex = targetBlockIndex + 1;
+			}
+
+			_nextItemIndex = itemsSpan.Length;
+			_longCount = targetCapacity;
+			_lastBlockWithData = targetBlockIndex;
+		}
+
 		public void AddRange(RecyclableLongList<T> items)
 		{
 			if (items.LongCount == 0)