public class MyClass
{
    public string Text { get; set; }
    public string Value { get; set; }
}

class Program
{ 
    public static List<MyClass> Create()
    {
        List<MyClass> myClass = new List<MyClass>() { new MyClass { Text = "один", Value = "1" } };
        return myClass;
    }

    static void Main(string[] args)
    {
        foreach(var i in Create())
        {
            Console.WriteLine(i.Text);
        }

        Console.Read();
    }
}

    
public static List<MyClass> Create()
{
    List<MyClass> myClass = new List<MyClass>() { new MyClass { Text = "один", Value = "1" } };
    MyClass myClass2 = new MyClass { Text = "два", Value = "2" };
    myClass.Add(myClass2);
    return myClass;
}

return myClass.Add(myClass2);

return (List<MyClass> )myClass.Concat(new List<MyClass>() { myClass2 });

public static class MyExtensions
{
    public static List<MyClass> AddItem(this List<MyClass> list, MyClass myClass)
    {
        list.Add(myClass);
        return list;
    }
}

return myClass.AddItem(myClass2);

return new List<MyClass> myClass = new List<MyClass>()
 {
   new MyClass { Text = "один", Value = "1" },
   new MyClass { Text = "два", Value = "2" }
 };

...
 public static IList<MyClass> Create()
 {
  return new MyClassList()
  {
   { "один", "1" },
   { "два", "2" }
  };
 }
}

public class MyClassList : List<MyClass>
{
 public void Add(string text, string value)
 {
  Add(new MyClass(text, value));
 }
}

public class MyClass
{
 public MyClass(string text, string value)
 {
  Text = text;
  Value = value;
 }
 public string Text { get; protected set; }
 public string Value { get; protected set; }
}

...
 public static IList<MyClass> Create()
 {
  return new MyClassList().Add("один", "1").Add("два", "2");
 }
}

public class MyClassList : List<MyClass>
{
 public MyClassList Add(string text, string value)
 {
  Add(new MyClass(text, value));
  return this;
 }
}
...