Lab Rats (White/Pinkish Rats)
Caterpillars,
Butterflies
Horses (Besides the unicorn)
Hogs (or a Hog Skin for the piggy!)
T-Rex
Hens
Probably a Cockroach
Penguins, Emperor penguins to be more precise.
For potential Collabs there can be:
Puyo Puyo Tetris: Risukuma and Ai.
Sanrio: Hello Kitty, Cinnamon Rol, Etc.
Chikn Nuggit: All the crew qualifies :3