LevelMeshToolProvider.cs

using System.Collections.Generic;
using System;

public static class LevelMeshToolProvider
{
 private static IEnumerable<Type> GetAllTypes(AppDomain domain)
 {
   foreach (var assembly in domain.GetAssemblies())
   { 
      Type[]  types = assembly.GetTypes();
      foreach (var type in types)
       {
         yield return type;
       }
    }
  }
}