Which Pokemon can have Mega Evolution states?
The Pokemon that have mega evolutions at the moment are somewhat arbitrary, in my opinion. Notably the only starters on the list are the Kanto starters (one of which has TWO versions) and Blaizken, and there are no new sixth generation Pokemon with a mega evolution! According to Serebii this is the current list (and this is believed to be final at this point, as there are no other known mega stones).
- Venusaur
- Charizard (two formes, X and Y)
- Blastoise
- Alakazam
- Gengar
- Kangaskhan
- Pinsir
- Gyarados
- Aerodactyl
- Mewtwo (two formes, X and Y)
- Ampharos
- Scizor
- Heracross
- Houndoom
- Tyranitar
- Blaziken
- Gardevoir
- Mawile
- Aggron
- Medicham
- Manectric
- Banette
- Absol
- Garchomp
- Lucario
- Abomasnow
Note that most mega evolutions have different abilities, and a few even change their typing!
Whilst the list above is still true for Pokemon X & Y - Pokemon Omega Ruby and Alpha Sapphire have introduced new Mega Evolutions:
- Beedrill
- Pidgeot
- Slowbro
- Steelix
- Sceptile
- Swampert
- Sableye
- Sharpedo
- Camerupt
- Altaria
- Glalie
- Salamence
- Metagross
- Latias
- Latios
- Rayquaza
- Lopunny
- Gallade
- Audino
- Diancie
As well as the two 'Primal Reversion' Evolutions
- Kyogre
- Groudon