Pokkén Tournament
At the end of a recent trailer, Shadow Mewtwo has been revealed. It will likely be a playable character in the Wii U version. It is possible that this is similar to the Shadow Lugia from Pokémon XD.

Event Zoroark
A Mystery Gift Zoroark is available to download in Omega Ruby and Alpha Sapphire in North America. This Zoroark knows the special move Sludge Bomb, which it cannot normally learn and is an important move for competitive play.