What type of dog mates the best with a golden retrivers?

Any breed of dog (or mixed breed) can mate with any other dog. I don't think there is any one breed that works "best", when looking to create a litter of mixed breed dogs. Rather, consider what traits you'd like to puppies to possess. Are you looking for a short haired dog? A dog with a sweet temperament? Do you want larger dogs, or smaller?

To help better ensure the puppies actually have some of the traits you're trying to achieve, it would be best if both parents were purebred. If either of the parents are themselves mixed breed dogs, there's no way to tell what gene pool you're dealing with.