I think one of the key things here is to find out what your dog really loves, and remember that it doesn't have to be one kind of treat, or even food at all. Dogs can be motivated by any number of things to varying degrees:
Within each of these categories you can see differing reactions. For example, a dog might enjoy getting kibble, but go crazy for a piece of cheese. Another dog might not care for either but really love playing tug or chasing a ball.
Think about some of the things your dog really loves (and it can be literally anything that won't hurt them) and then use that as a reward. Here are some examples to give you an idea of the range of rewards
Food: Food fed for dinner, kibble not used at mealtimes, any variety of dog treats, hot dogs, cheese, boiled chicken, salmon
Toys: Tugging on fluffy toys, tugging on hard toys, chasing a ball, chasing a frisbee, catching a ball, chasing a person, chewing on a bone, playing with an old sock
Experiences: Verbal praise, extra games, petting, shoving, chasing a squirrel, sniffing a garden, rolling in something smelly, meeting someone new, working with their person, learned cues
The possibilities are endless, but finding the right motivation can be difficult. Once you've found out what motivates your dog, you can then use that to your advantage. Make sure that you're controlling the reinforcement though because if he learns he can just give up and come get treats from your pocket, he'll do that. Dogs are great trainers of their humans.