This Is a list of Complete Confirmation on Mega Evolutions... Bottom list show a list of high chance of pokemon having mega evolutions!
Also to note the bottom list has had alot of pokemon comfirmed for mega evolutions before they were even announced 
★List of Confirmed★
Mega Venusaur
Mega Blastoise
Mega Charizard X
Mega Charizard Y
Mega Absol
Mega Mewtwo X
Mega Mewtwo Y
Mega Abomasnow
Mega Gyarados
Mega Mawile
Mega Tyranitar (A ballon of Super Training Shown) not 100%
Mega Gengar
Mega Ampharos
Mega Lucario
Mega Blaziken
Mega Aggron (A ballon of Super Training Shown) not 100%
Mega Kangaskhan
Mega Garchomp
Mega Gardevoir
Mega Aerodactyl
☆List of pokemon that could have Mega Evolutions☆ (◆= Confirmed to have a Mega)
[First List consist of Before BW2 Was Released]
◆Charizard, ◆Blastoise, ◆Gengar, ◆Kangaskhan, Pinsir, Jynx, ◆Gyarados, ◆Aerodactyl, ◆Mewtwo
◆Ampharos, Scizor, Houndoom, Tyranitar, Heracross
◆Gardevoir,◆ Absol, Medicham, Banette, Latias, Latios, Aggron
◆Abomasnow
[List shows after BW2 was announced!]
Jynx,Scizor,Medicham,Banette,Kyogre,Kecleon,Latias,Latios,Pinsir,Houndoom,Groudon,Aggron,Plusle,Minun,Sceptile,Rayquaza,Heracross
http://pokemonfigure.blogspot.jp/2013/08/registered-trademark-and-mega-pokemon.html?spref=tw
