They've been doing it for years, it's called Pokemon Events. You go to your local gamestop and download a pokemon.
those are really trades though even though you dont give anything back dont consider dlc
and that's free for the most part
Im talking about how Mario has new levels and Pokemon dungeon has new dungeons(paid dlc). Meaning something that's not in the game already maybe a new town a new zone or idk what else they could do (formes after the game )
and maybe it could be used to make trading with newer games later on posible example pokemon z is released 1.5 years later and introduces a new forme to a preexisting pokemon. (this sounds more like a patch though nvm)
Not all DLC is paid. Why do you want paid DLC?
Currently awaiting: Pikmin 3, Lunar Knights 2, LM:DM, AC:NL, XY, X, WW HD, LoZ U, LR:FFXIII, FFVXIII Skarmory would slap the hell outta you