He doesn't like the barbell ones very much, and I've never seen one at any of the stores around town. If I get him a bigger Kong I'm not sure if he'll treat it like a bouncy ball. I don't think he'd even like it.
The plush toys, well, I got one for him and he likes it, but not very much.
He seems to like pom-poms, but I can't find any that are strong enough so he can't pull them apart.