C#

if(!list.contains("Method"))
   list.add("Method");

foreach(...)
{
   if(!myList.Contains(myClass))
      myList.Add(myClass);
}

public override bool Equals(object obj)
{
   if (obj == null)
      return false;
   MyClass m = obj as MyClass;
   if (m == null)
      return false;

   return Name == m.Name && Value == m.Value;//you need to compare all relevant values here
}

public override int GetHashCode()
{
   return Name.GetHashCode() ^ Value;
}

List<string> list = new List<string>();
list.Add("Method");
list.Add("Method");
list.Add("Method2");
list.Add("Method");

List<string> res = (from _ in list group _ by _ into __  select __.Key).ToList();

List<string> res = new HashSet<string>(list).ToList();