diff --git a/BeefLibs/corlib/src/Collections/Dictionary.bf b/BeefLibs/corlib/src/Collections/Dictionary.bf
index 32fca56a..9789c46d 100644
--- a/BeefLibs/corlib/src/Collections/Dictionary.bf
+++ b/BeefLibs/corlib/src/Collections/Dictionary.bf
@@ -267,7 +267,11 @@ namespace System.Collections
 			}
 			else
 			{
-				//TODO: IMPORTANT!
+				for (int_cosize i = 0; i < mCount; i++)
+				{
+					if (mEntries[i].mHashCode >= 0 && mEntries[i].mValue == value) return true;
+				}
+				//TODO: comparison
 				/*EqualityComparer<TValue> c = EqualityComparer<TValue>.Default;
 				for (int i = 0; i < count; i++)
 				{
diff --git a/BeefLibs/corlib/src/Collections/List.bf b/BeefLibs/corlib/src/Collections/List.bf
index 605cb723..90423812 100644
--- a/BeefLibs/corlib/src/Collections/List.bf
+++ b/BeefLibs/corlib/src/Collections/List.bf
@@ -930,6 +930,59 @@ namespace System.Collections
 		}
 	}
 
+	extension List<T> where T : String
+	{
+		public bool Contains(T item, StringComparison comparison)
+		{
+			if (item == null)
+			{
+			    for (int i = 0; i < mSize; i++)
+			        if (mItems[i] == null)
+			    		return true;
+			    return false;
+			}
+			else
+			{
+				for (int i = 0; i < mSize; i++)
+					if (mItems[i].Equals(item, comparison))
+						return true;
+			    return false;
+			}
+		}
+
+		public int IndexOf(T item, StringComparison comparison)
+		{
+			for (int i = 0; i < mSize; i++)
+				if (mItems[i].Equals(item, comparison))
+					return i;
+			return -1;
+		}
+
+		public int IndexOf(T item, int index, StringComparison comparison)
+		{
+			for (int i = index; i < mSize; i++)
+				if (mItems[i].Equals(item, comparison))
+					return i;
+			return -1;
+		}
+
+		public int IndexOf(T item, int index, int count, StringComparison comparison)
+		{
+			for (int i = index; i < index + count; i++)
+				if (mItems[i].Equals(item, comparison))
+					return i;
+			return -1;
+		}
+
+		public int LastIndexOf(T item, StringComparison comparison)
+		{
+			for (int i = mSize - 1; i >= 0; i--)
+				if (mItems[i].Equals(item, comparison))
+					return i;
+			return -1;
+		}
+	}
+
 	class ListWithAlloc<T> : List<T>
 	{
 		IRawAllocator mAlloc;
diff --git a/BeefLibs/corlib/src/Diagnostics/Check.bf b/BeefLibs/corlib/src/Diagnostics/Check.bf
index 0b26b71c..b041f6fb 100644
--- a/BeefLibs/corlib/src/Diagnostics/Check.bf
+++ b/BeefLibs/corlib/src/Diagnostics/Check.bf
@@ -1,6 +1,6 @@
 namespace System.Diagnostics
 {
-	class Check
+	static class Check
 	{
 
 		[Unchecked, SkipCall]
diff --git a/BeefLibs/corlib/src/Diagnostics/Contracts/Contracts.bf b/BeefLibs/corlib/src/Diagnostics/Contracts/Contracts.bf
index e14d5a0c..e5f7d80c 100644
--- a/BeefLibs/corlib/src/Diagnostics/Contracts/Contracts.bf
+++ b/BeefLibs/corlib/src/Diagnostics/Contracts/Contracts.bf
@@ -1,6 +1,6 @@
 namespace System.Diagnostics.Contracts
 {
-    class Contract
+    static class Contract
     {
         public enum ContractFailureKind
         {
diff --git a/BeefLibs/corlib/src/Diagnostics/Debug.bf b/BeefLibs/corlib/src/Diagnostics/Debug.bf
index d4df7bd4..fe45865b 100644
--- a/BeefLibs/corlib/src/Diagnostics/Debug.bf
+++ b/BeefLibs/corlib/src/Diagnostics/Debug.bf
@@ -1,6 +1,6 @@
 namespace System.Diagnostics
 {
-	class Debug
+	static class Debug
 	{
 #if !DEBUG
 		[SkipCall]
diff --git a/BeefLibs/corlib/src/IO/File.bf b/BeefLibs/corlib/src/IO/File.bf
index a3ae6cf2..06d6abd7 100644
--- a/BeefLibs/corlib/src/IO/File.bf
+++ b/BeefLibs/corlib/src/IO/File.bf
@@ -23,7 +23,7 @@ namespace System.IO
 		case FileReadError(FileReadError);
 	}
 
-	class File
+	static class File
 	{
 		public static Result<void, FileError> ReadAll(StringView path, List<uint8> outData)
 		{
diff --git a/BeefLibs/corlib/src/Runtime.bf b/BeefLibs/corlib/src/Runtime.bf
index 96ae54fc..564b032c 100644
--- a/BeefLibs/corlib/src/Runtime.bf
+++ b/BeefLibs/corlib/src/Runtime.bf
@@ -6,7 +6,7 @@ using System.Threading;
 namespace System
 {
 	[StaticInitPriority(100)]
-	class Runtime
+	static class Runtime
 	{
 		const int32 cVersion = 8;
 
diff --git a/BeefLibs/corlib/src/System.bf b/BeefLibs/corlib/src/System.bf
index def9c456..9289da0a 100644
--- a/BeefLibs/corlib/src/System.bf
+++ b/BeefLibs/corlib/src/System.bf
@@ -227,6 +227,26 @@ static
 		}
 	}
 
+	public static mixin DeleteContainerAndDisposeItems(var container)
+	{
+		if (container != null)
+		{
+			for (var value in container)
+				value.Dispose();
+			delete container;
+		}
+	}
+
+	public static mixin ClearAndDisposeItems(var container)
+	{
+		if (container != null)
+		{
+			for (var value in container)
+				value.Dispose();
+			container.Clear();
+		}
+	}
+
 	public static mixin DeleteAndNullify(var val)
 	{
 		delete val;
diff --git a/BeefLibs/corlib/src/Text/UTF16.bf b/BeefLibs/corlib/src/Text/UTF16.bf
index 4a4953f2..5ab1fc6d 100644
--- a/BeefLibs/corlib/src/Text/UTF16.bf
+++ b/BeefLibs/corlib/src/Text/UTF16.bf
@@ -1,7 +1,7 @@
 using System.Diagnostics;
 namespace System.Text
 {
-	public class UTF16
+	public static class UTF16
 	{
 		public enum EncodeError
 		{
diff --git a/BeefLibs/corlib/src/Text/UTF8.bf b/BeefLibs/corlib/src/Text/UTF8.bf
index 4df4c7f9..0dce24ae 100644
--- a/BeefLibs/corlib/src/Text/UTF8.bf
+++ b/BeefLibs/corlib/src/Text/UTF8.bf
@@ -1,7 +1,7 @@
 using System.Diagnostics;
 namespace System.Text
 {
-	class UTF8
+	static class UTF8
 	{
 		public const int8[256] sTrailingBytesForUTF8 =
 		.(