Jackson goes crazy for Crumps, they look like this:
Amazon
He also loves Soft n Chewy Buddy Biscuits a lot. I like the Cloud Star products. We rotate between flavors but his fav BY FAR is this bacon and cheddar flavored ones.
Ummm... what else...? Oh, he loves the Bravo! treats, the tiny freeze dried ones. We don't buy them a lot because they're pricey.
High value rewards are usually string cheese or real meat, i.e. chicken breast.