The booster pack art will feature Alolan Vulpix, Lugia, Regidrago, and Regieleki as the set mascots
In this case, it's price: Mana Crypt is nearly $200 USD at this point
In Pokmon GO itself, Ditto also hides in plain sight behind a rotating cast of Pokmon including Bidoof, Pidgey, Ekans, and so on, and only once you catch one does "Oh?" appear on the screen before revealing that you actually just caught a Ditto
The XY set is the first set in the XY series confusing right
My final advice would be: use the basic frame structure as a constraint (limitation breeds creativity, Mark Rosewater says), and if needed work from there to create new details that are really meaningful for the game, and be more careful not to create more noise