RD Padouk
Sodbuster
I think it would be cool to be able to cross-breed slimes in a more interesting way to create stable colors, much like the way flowers are done in Animal Crossing. Not all slimes, but maybe a small subset? It would add an interesting angle to the game. Of course, cross-breeding anything would be cool, but slimes seem the most straight forward since there is already a basic capability built in.