Couldn't be bothered with finding the other threads.

[hider=Spoilers from Serebii.net][img=http://serebii.net/corocoro7141.jpg]
Mega Diancie, possibly with a new Ability but with the same type as before. Mega Sceptile is Grass/Dragon now, Charizard style, only with a near-useless ability in Lightningrod (already quad-resists). Mega Swampert stays the same typewise, but gets ripped. No new streamlining but apparently its ability is Swift Swim. No Sap Sipper for you.

[img=http://serebii.net/corocoro7142.jpg]
Not much new information concerning Mega Groudon and Kyogre.

A bunch of Hoenn characters are also shown to be returning with minor redesigns but bluh images. Go to Serebii. :\[/hider]