What breed of dog should I get?

ok, so I already have two Border Collies. I am retiring my youngest from the 4-H Dog show circuit. I want to get another dog so that I can keep showing. I think that I would prefer a dog that is smaller than a Border Collie. I want a dog that's small in size, very entergetic, very easy to train, and that is very adaptable. Any dog breed recomondations would be appreciated!! Thanks so much for your time!!