Okay, I admit, this idea isn't original, but it's workable. The idea is rather simple: Make a team based on a certain animal etc: Mouse, Horse. (Plants are acceptable, but only to one type of plant etc Lettuce, Weed) Legendaries are acceptable BUT. BUT BUT BUT. You can only use one. And that Legendary cannot be in the Ubers tier. Fossils are allowed as animals.
Have fun!
EDIT: After consideration, birds are banned. Half Animal teams are banned etc Half Monkey Half Dog team. Human-lookalike are considered Monkeys etc Gallade. Pokemon with unclear status are not allowed etc Meinshao. Arceus is a freaking Deer, not a goat, stop asking!