i have found a really good order to go in for mission cards, note i made it to 16 in expert stages and 150 in normal, do mission card 1 2 8 10, 1 is really easy, 2 holds a mega stone, 8 and 10 also have mega stones, eh i might be crazy or being really helpful, you can decide to do or ignore... i just suggesting this order for mega stones cause those are good