On the off chance that you're into games like, say, Pokemon, there's a lesser known monster game for the GBC called Magi-Nation--and no, I don't mean that gay cartoon made by Cookie Jar with the brown haired child and the psuedo-rock music in the intro--I mean the original GBC game based on the CCG, Magi-Nation Duel.
My avatar, for instance, is from that game. I don't know if it's better than Pokemon, but it's worlds improved from other monster games like Azure Dreams and Dragon Warrior Monsters.