Hello and welcome to the past PU metagames viability rankings. Unlike the history of the viability rankings, this will actually be updated as the metagames change. This is mainly used as a resource for PUPL, though it's also for trying to develop these past metagames a bit and keep things updated as the metagames are played (including probably updating the August and XY rankings with threats that were discovered later, like Jumpluff for example). Also, note that XY PU has Chatter and Smashpass banned, as per PUPL. Anyway, here are the rankings:
BW PU
XY PU
August PU
BW PU
BW PU
XY PU
August PU
BW PU
Unranked (as of yet)
S-rank
A-rank
B-rank
C-rank
D-rank
E-rank
Everything else.