I haven't tried a lot of things, but I know my horses love granola bars and fruit bars. Some like just a bun or slice of bread. My neighbor's horse loves hot dogs.
My friend's old horse went crazy for cooler ranch doritos...
Hmm...I made apple cinnamon muffins (for which I got the recipe from a horse treat book), but they were edible for people too...and they were GOOD!
Peppermints are always a sure thing for most horses I've been around. One horse I knew would drink iced tea from a cup, like a person. She'd grab it and tilt her head back, then throw the cup down when she was done, lol.
Let's see....Cheerios...granola cereal..my brother has been eating it and I sneak some out to the horses when he's not home..teehee.
Twizzlers....
One horse I rode loved Mountain Dew..I let him have a taste and didn't think he'd like it, but he did. I didn't let him have any more of it though..