ExampleBehaviour.cs

using System;
using System.Collections.Generic;
using System.Linq;
using Sirenix.OdinInspector;
using Sirenix.OdinInspector.Editor;
using Sirenix.Utilities;
using UnityEngine;

public class ExampleBehaviour : MonoBehaviour
{
	[TypeSelector]
	public int myField;
	
	[TypeSelector(typeof(Collider))]
	public int myOtherField;
}

public class TypeSelectorAttribute : Attribute
{
	public readonly Type BaseType;
	

	public TypeSelectorAttribute(Type baseType = null)
	{
		BaseType = baseType;
	}
}

public class TypeSelectorAttributeDrawer : OdinAttributeDrawer<TypeSelectorAttribute>
{
	private static Dictionary<Type, string> customTypeNameDict = new Dictionary<Type, string>()
	{
		{typeof(CapsuleCollider), "My Custom Name"},
		{typeof(BoxCollider), "I don't know"},
	};
	private ValueDropdownItem<Type>[] _validTypes;
	

	protected override void Initialize()
	{
		if (_validTypes != null) return;

		var validTypes = AssemblyUtilities.GetTypes(AssemblyTypeFlags.All)
			.Where(x => !x.IsAbstract)
			.Where(x => !x.IsGenericType);
		
		if (Attribute.BaseType != null)
		{
			validTypes = validTypes.Where(x => Attribute.BaseType.IsAssignableFrom(x));
		}
		
		_validTypes = validTypes
			.Select( x => customTypeNameDict.TryGetValue(x, out var customName)
				? new ValueDropdownItem<Type>(customName, x)
				: new ValueDropdownItem<Type>(x.FullName.Replace('.', '/'), x))
			.ToArray();
	}

	protected override void DrawPropertyLayout( GUIContent label )
	{
		IEnumerable<ValueDropdownItem<Type>> results = OdinSelector<ValueDropdownItem<Type>>.DrawSelectorDropdown( GUIContent.none, "Select a type..", DoSelector );
		if ( results != null )
		{
			var selectedType = results.FirstOrDefault().Value;
			if (selectedType != null)
			{
				Debug.Log($"Selected type: {selectedType}"); // use selected type here
			}
		}
		GUILayout.Space( 2 );
		
		CallNextDrawer( label );
	}

	protected OdinSelector<ValueDropdownItem<Type>> DoSelector( Rect buttonRect )
	{
		GenericSelector<ValueDropdownItem<Type>> selector = new GenericSelector<ValueDropdownItem<Type>>( _validTypes );
		selector.ShowInPopup( buttonRect );
		return selector;
	}
}