For my younger dog clicker training amusing tricks is a great way to stimulate her brain. For my older spaniel, who was never clicker trained and isn't at all food motivated, we stick more to find it and retrieve games like your pup. Have you considered working on scent discrimination and tracking with your puppy? For a dog that is very nose oriented this is a very fun activity.
We also like to create difficult "puzzles" for him. These puzzles usually consist of a tennis ball wrapped in a sock, wrapped in another sock, wrapped in a shirt, wrapped in a blanket, stuffed inside a box, stuffed inside another box, etc... you get the point. He's never been the kind to chew on fabric so we tightly knot up clothes and blankets for him to untie while digging or pulling with his teeth. When he was younger this would keep him busy for a while. Now that he's older and an expert at this we stick more to tracking and scent discrimination.
