diff --git a/Engine.Core/Helpers/FastList.cs b/Engine.Core/Helpers/FastList.cs
index fa64216..89b11b3 100644
--- a/Engine.Core/Helpers/FastList.cs
+++ b/Engine.Core/Helpers/FastList.cs
@@ -3,14 +3,15 @@ using System.Collections.Generic;
 
 namespace Engine.Core;
 
-public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
+public class FastList<T> : IList<T>, IReadOnlyList<T>, IEnumerable<T> where T : notnull
 {
     private readonly List<T> items = [];
     private readonly Dictionary<T, int> indexMap = [];
 
     public int Count => items.Count;
 
-    public T this[int index] => items[index];
+    public bool IsReadOnly { get; set; } = false;
+    public T this[int index] { get => items[index]; set => items[index] = value; }
 
     public void Add(T item)
     {
@@ -66,6 +67,9 @@ public class FastList<T> : IReadOnlyList<T>, IEnumerable<T> where T : notnull
             indexMap[items[i]] = i;
     }
 
+    public int IndexOf(T item) => items.IndexOf(item);
+    public void CopyTo(T[] array, int arrayIndex) => items.CopyTo(array, arrayIndex);
+
     public IEnumerator<T> GetEnumerator() => items.GetEnumerator();
     IEnumerator IEnumerable.GetEnumerator() => GetEnumerator();