Pony Pokemon cards seem to make a bit more sense. You don't need them to evolve for them to be interesting, and you can really add some nice card effects. There are a lot of different card types that just seem to synergise perfectly with the fandom of MLP, such as types, Legends, Lv X, Pokemon EX, and so on, but still with the evolution options. Image citation has been added as a comment by me.