Not sure about Cloyster. Although C-Rank is pretty decent justice for Cloyster; it needs a shit ton of support to work, especially with that horrid SpD, awful defensive typing, and shitty HP. Ughhh.
Anyways, prepare for a tl:dr post; I'm up for a whole lot of nominations.
Firstly, I'd like to nominate Abomasnow for
B-Rank, if not A-Rank (though the latter unlikely). It is the summoner of its own weather; hail. Abomasnow is the crux of any hail team, to spam Blizzards, etc. The fact that it is a summoner of weather itself also makes it a great check to Tyranitar and Politoed alike, neutering their weather and just smashing them. Of course, his shit typing makes that rather hard, which is why I say "check". Same with the mighty Hippo, who gets chills from Blizzard. Also, CB Aboma can smash Ninetales with EQ or Focus Punch. Abomasnow has great STAB's too, and they provide great coverage. His mixed attacking stats are nice to do some real good, and his stats overall allow him to fulfill the role of a weather killer with CB, or a Mixed Attacker, or even a SubSeeder. While he's not the best Pokemon ever, and is slow, yes. But his hail summoning shit and being a good weather killer and mixed attacker should get him up some. But that's just what I think.
It's a disgrace that a pathetic nine tailed fox sits in the A-Rank while a mighty abominable snowman gets the C-Rank.
Also gonna nominate Darmanitan for
C-Rank. Darma is strongth. Like, damn powerful that in the sun, it is nigh impossible to take a Flare Blitz from this nigga. He can hit pretty damn hard, has an alright speed tier, although still outsped by a number of things. With a Scarf or LO, he can do a solid job as a powerhouse in the sun, and can take down a lot of shit. Of course, though, in this weather centered meta, he gets nerfed hard by rain, and so he absolutely
needs the sun to be consistent. Also, Sand makes life hard to some degree for Darma, so yeah. Also, he's SR weak, and combined with the liability of pathetic Ninetales, that's no good. You need a spinner like Donphan or Starmie to be successful. But his effectiveness provided the right support can place him in the
C-Rank.
I'm also gonna bring back up Takion's nomination of Bisharp in
D-Rank. Bisharp is usable in OU. With 125 Attack, a great boosting move in Swords Dance, a myriad of resistances, and strong priority in Sucker Punch, Bisharp has just enough to be modestly viable in OU. He can switch in on a Pokemon after they clicked DM or Outrage, so he can set up, and be a vicious sweeper outright. His power is pretty damn strong and can hit a lot for serious damage after a boost, like Alakazam, non sub Gengar, Starmie, Celebi, etc. Defiant also discourages Landorus-T, so he's an alright check to that. But however, he has noticable flaws that make him go no higher than D-Rank, like a massive Fighting weakness, which makes him vulnerable to Lucario and Terrakion unless he is behind a Sub, in which case he can just hit 'em with Low Kick or Brick Break (or even Iron Head in the latter's case). He also has a low Speed tier, which makes him ridiculously reliant on Sucker Punch. He's also a pretty frail Pokemon on the special side, so beware. Also, faces very stiff competition from Scizor as a "Steel-type spam priority user" But still Bisharp has a small amount of viability in OU, and that alone should put him in the
D-Rank.
Also nominating Ninjask for
D-Rank. Ninjask has a small niche in OU with Speed Boost+Baton Pass. This famous niche can make or break a game. He does, however, have a SR weakness and is predictable, etc. So he should be
D-Rank.
Finally, nominating Quagsire for
D-Rank. Small niche, too tired to explain.
Original Post
Anyways, all I gotta say.