One thing I've noticed Blu doesn't like is Peppermint.
Now that I think about my friend's friend's gelding...he would eat anything! Literally. When he was younger I guess he swallowed a T-shirt and my friend's friend had to stick her arm in his mouth to pull out so he wouldn't choke.
Animal crackers(i think these are her favorite!)
The little round pellet things in apple flavor
(I know some are a little wierd. When I'm eating something near her I give her a little piece- that's where the pretzels, animal crackers, and chewy bars came from