string Comb = Combinations[UnityEngine.Random.Range(0, Combinations.Count - 1)];

class BaseClass
{
      public int X {get;}
      public int Y {get;}
      public BaseClass(int x, int y)
      {
            X = x;
            Y = y;
      }
}

class MyClass : BaseClass
{
      public MyClass(int x, int y) : base(x, y) //Передача параметров
      {
      }
}