so far, here's what's found : gengar, scizor, pinsir, aerodactyl, lucario, kanga, gyarados, absol, alakazam, garchomp, sableye, metagross, sharpedo, slowbro, glalie, salamence
it's simple : is the pokemon in the aloladex? if not, no stone in the battle tree shop. It might be elsewhere, given that you can get red/blue orb and soul dew.
Thank you a lot Kainazoo.
That means current OU Mega which are legal consist of:
Aerodactyl, Pinsir, Scizor, Gyarados, Absol, Alakazam, Garchomp, Sableye, Metagross, Sharpedo, Slowbro and Glalie.
This is a huge difference... to what is allowed during ORAS.