Inspired by siilence's idea of bred Store pets, here are some more suggestions! ^^
(I wouldn't make these free outcomes, but have like 4-5 next gen that can be bought like normal store pets. Or I supose if you wanna do more like a gacha, you could have people pay the usual 20C$ for 1 or 17-18C$ for 5 can see what random outcome they get)
Eastern Water Dragon
Poisoned Tea
Nature Fairy
Sunset Angel