Mega Slowbro and
Mega Audino accidentally both got leaked.
Mega Slowbro has the ability Shell Armor. Mega Audino is
Normal/Fairy-type and has the ability Healer.
Mega Slowbro vid here:
Mega Audino vid here:
Also other Mega's recently released:
Mega Altaria is a
Dragon/Fairy type, with the ability Pixilate. It also gets increased Special Attack & Attack stats, as well as boosted Defense.
Mega Lopunny is a Normal/Fighting type, with the ability Scrappy. It also gets highly boosted Attack & Speed stats.
Mega Salamence has the ability Aerilate. It also gets a highly boosted Defense stat.
Unsurprisingly, Steven's trump card is his
Mega Metagross. It's ability is Tough Claws. It also has a greatly increased Speed stat, with lesser boosts to all it's other stats.
Video showcasing several Mega's, contests and cosplay Pikachu's here:
Video showcasing Gym Leaders, Elite Four members, Cosplay Pikachu, secret bases and Mega Metagross: