B Rank: Reserved for Pokemon that are great in the Averagemons metagame. These Pokemon have more notable flaws than those above them that affect how they function in the tier. Their positive traits still outshine their negatives, but they require a bit more team support to bring out their full potential. These Pokemon exert an above average presence in the metagame.
B+ Rank:
Arceus-Normal Might put it at A- bc of its crazy unpredictability
Arceus-Rock Yup
Blaziken Speed Boost+typing and movepool is too good for B+. Sweeping is obvious, but Protect also lets you RK anything that hasn't boosted speed, which is huge. A-.
Gardevoir Yup
Gyarados-Mega Yup
Jirachi Tons of utility, decent typing, Serene Grace is Serene Grace. I prefer this to Klefki any day, honestly, although I can see the merit of Klefki on HO. Same rank as Klefki.
Mawile Haven't really seen this in action.
Rayquaza-Mega Yup
Skarmory Yup
Slowking Yup
Swirlix/Slurpuff A-, if not A. How the hell is this B+.
Tauros Yup
Victini Yup
B Rank:
Alomomola Haven't seen it but sure.
Altaria-Mega Pixilate is pretty great, typing is pretty great, movepool is decent enough. B+
Audino Haven't seen it but sure.
Breloom PH is unique and it has the tools it needs to be annoying, but it just isn't that threatening. B is good.
Excadrill Haven't seen it but yup.
Gorebyss Smashpass is dangerous AF, especially when you can pressure without passing as well. B+
Ho-oh Sacred Fire+Regenerator is great, but (as always) SR weakness sucks. B is good.
Huntail See Gorebyss, the two are pretty similar. I haven't really analyzed their respective merits, but if one clearly outclasses the other that should be accounted for.
Lucario-Mega Adaptability+good movepool=stronk. B+
Masquerain Inheritance taught us that Masquerain can be amazing w/o its typing, but unfortunately it has that typing, and that typing sucks. B-
Ninetales Haven't seen it but sure.
Pawniard/Bisharp Yup.
Porygon-Z Outclassed by Chatot+Exploud. I really don't see what this thing's niche is. B-
Primal Kyogre Haven't seen it but sure.
Solrock Good typing+ability and decent movepool. Provides unique support. B+
Staryu Amazing bulky water that spins and does stuff. B+, maybe even A-.
Thundurus Haven't seen it but sure.
Tornadus-Therian Haven't seen it but sure.
Yveltal Dark Aura Knock Off+Sucker Punch are powerful, and Oblivion Wing is cool. Outclassed by Crawdaunt in offensive roles, though, and defensive roles are hurt by SR weakness. B seems good.
B- Rank:
Aerodactyl Haven't seen it but sure.
Banette-Mega Prankster DBond is nice, I guess. B- seems good.
Darkrai Dark Void is cool, as we all know, but the real kick is that it has SD+NP+mixed coverage, so it boasts unpredictability offensively as well. B
Ditto Loads of setup sweepers are nice for it, but since Ditto is hella weird to rank we can leave it here.
Furfrou Idgaf if it lacks reliable recovery, this thing is literally the most physically bulky wall in the metagame and it can use Restalk. A staple on stall which merits at least B+.
Genesect Espeed+Explosion+U-turn+Download is nice for fast Volt-turn teams, and Shift Gear lets you capitalize on an physical Download boost to clean up. B
Gyarados Haven't seen it but sure.
Heatran Sure.
Hippopotas/Hippowdon Haven't seen it but sure.
Kabutops Haven't seen it but sure.
Kingdra Critdra is deadly, albiet tricky to set up. B, maybe even B+
Malamar Haven't seen it but sure.
Manaphy Haven't seen it but Tail Glow seems, from a theoretical perspective, to be super strong. Again, though, I haven't seen it, so I lack a practical opinion.
Mew Haven't seen it but sure.
Mienshao Great Regenvest pivot with limited but satisfactory movepool options. B+, maybe even A- but I'm personally biased in that I really really like it lol
Numel Underwhelming from experience, as Scalds are everywhere, but nonetheless threatening. B- is ok.
Shaymin-Sky Haven't seen it but sure.
Shuckle Interesting movepool which works in conjunction with Sturdy. I'd put it at B.
Surskit Sure.
Sylveon Haven't really seen it, but an ability like Pixilate seems misplaced this low. Maybe B?
Volbeat TGPass is scary af going into ScarfOgre or something similar. B, maybe even B+ if Gorebyss/Huntail go up there too.
tl;dr:
Arceus-Normal to A-
Blaziken to A-
Jirachi to wherever Klefki ends up
Swirlix/Slurpuff to A-/A
Altaria-Mega to B+
Gorebyss to B+
Huntail to B+
Lucario-Mega to B+
Masquerain to B-
Porygon-Z to B-
Solrock to B+
Staryu to B+/A-
Darkrai to B
Furfrou to B+
Genesect to B
Kingdra to B/B+
Mienshao to B+/A-
Shuckle to B
Sylveon to B
Volbeat to B/B+