I've been setting up NPCs, trying to use the in-built "Tier" dropdown under their Battle Rules, but the Banlist is very minimal.
I've tested for OU, trying to use all the Ubers (Gen 7), and it ended up only banning the following:
Blaziken-Mega (does not ban Base Blaziken, even with Speed Boost)
Darkrai
Dialga
Gengar-Mega
Ho-oh
Kangaskhan-Mega
Landorus
Lucario-Mega
Lugia
Mewtwo-Mega Y/X (does not ban Base Mewtwo)
Palkia
Reshiram
Salamence-Mega
Yveltal
Zekrom
Assuming that the Banlist is supposed to ban gen6 ubers, Greninja and Sableye-Mega are not banned either.