There are many many flavors you can chose from, eh?
Yugioh, Pokemon, Magic, Baseball, Basket Ball, Poker, Zatch Bell- any of these cards! Also note ID Cards are good to chew on incase you're in need of something to chew on at a place that only has ID Cards.
But yeah, you're not the only one who chews on Cards :0. I chew on my unneeded Yugioh and Pokemon cards all the time!