CLAMP has a lot of mascots. Off the top of my head, there's that balloon-fish-like thing from CLAMP in Wonderland, the crabs from their doujin days, the God-bunnies from Wish, Ioryogi, monkeys, Atashi...
I'm still extremely attached to CCS, so I'd have to say I love Kero-chan best. I'm still waiting for him to appear in Tsubasa. Suppi-chan has my love too, when he's drunk.