stay away from hooves - they are harder than the dog's teeth and can chip teeth.
Training treats are anything that the DOG finds reinforcing. This is what I've used at my house with my basenjis for training treats: chicken, meatballs, waffles, hotdogs, cheerios, baby food, bread, sweet potatoes, green beans, dog food, Zukes, steak, bacon (small amounts), playing chase, fetching, playing with other dogs, "hunting " rabbits, liver, eggs, dinner, cheese, walks, liverwurst, sniffing, etc. A top agility trainer talks about how one of her dogs LOVED playing with fly swatters; a friend of mine had a dog that would do anything for cole slaw (yuck!). Your list is limited by your imagination and your dog.