You can register an instance of an object by calling .Register() with the object reference as the only parameter. That automatically generates a singleton dependency.
public interface IMyService<T> {} public class MyService<T> : IMyService<T> {}
ServiceLocator.Register(typeof(MyService<>));
IMyService svc1 = ServiceLocator.Get<IMyService<int>>(); // svc1 = instance of MyService<int> IMyService svc2 = ServiceLocator.Get<IMyService<string>>(); // svc2 = instance of MyService<string>