A few nominations that may have been missed or forgotten about in chronological order (I think) -
Spritzee
Bronzor
Starly
Wooper
Slugma
Shellos
Houndour
Fletchling
Azurill
There were a few other noms (Remoraid, Trubbish, Elekid) that seemed really unpopular so I didn't include them. Also a nincada nom by fizz but nincada sucks so I'm not linking that either
Anyway, a few quick thoughts on some of the recent nominations:
Stunky: B-
I've never really liked Stunky because it has never really stuck out. It's fairly frail and has no defensive boons to make up for it, its offensive stats are a bit mediocre for an offensive Pokemon, and it can't actually hit 18 Speed if it plans on taking advantage of its standard mixed set to its fullest extent; its STAB moves also have somewhat average base powers, so I often find it not dealing as much damage as I would like it to. With that being said, I agree with it being moved to B-, but no higher than that due to its flaws. Gastly and Abra are enormous threats right now, posing as huge nuisances to defensive teams and heavily damaging most offensive teams as well; being able to switch into and get rid of them both is nothing short of amazing, and I cannot stress how strong of a niche this is, regardless of the fact that Stunky does little else. Defog is hardly a niche when pretty much every common defensive hazard setters and even some offensive hazard setters are able to easily outlast Stunky.
Bunnelby: A-
Bunnelby is really, really strong, and I think Misdreavus's ban absolutely made Bunnelby A- worthy. I can't speak for the Choice Scarf set because I haven't been using it much, but the Life Orb set has everything you could ever ask for in a wall-breaker. Everything except Pumpkaboo and Phantump is 2HKOed at worst by a simple set of Return/Quick Attack/Earthquake/Wild Charge; if Bunnelby comes in on something slower than it that it can KO, then it's all but guaranteed to get a KO because nothing wants to switch into it. The amount of pressure Bunnelby is able to put on more defensive teams is astounding, right up there with the likes of LO Abra and LO Gastly but with even less common switch-ins. Even against offensive teams it's far from a dead weight, because Quick Attack deals a ridiculous number to frailer Pokemon, and most things slower than Bunnelby are totally crushed by Return, turning Bunnelby into a great cleaner. I know Bunnelby is one of those Pokemon I often try to save to the end when using offense, simply because it's so valuable.
Vullaby: A-
Knock Off is, as we all know, an incredible move; as such, STAB Knock Off is amazing. The problem with Pawniard when it tries abusing it is that it has a ton of trouble against the ubiquitous Fighting-types; Vullaby, on the other hand, actually serves as a check to these Fighting-types because Brave Bird can heavily damage them, even without investments. This allows Vullaby to spam a fairly powerful and very detrimental Knock Off much more freely, outside of Trubbish. In addition, everybody knows that Foongus is easily the best Pokemon ever, and Vullaby completely walls it. I have been seeing Foongus around a lot noticeably, and being one of the few Pokemon that can switch into Foongus over and over and completely wall it is a much more notable niche than it once was. I have been including Vullaby on a lot of my teams recently because it can check so many things in one slot, including Gastly, Abra, sun sweepers, Fighting-types, and most importantly, Foongus, while doing so throughout the match thanks to Roost and still providing extremely useful Defog support.
Supporting Ekans for C, Ferroseed for A and Pumpkaboo for C+ for reasons already mentioned which I won't bother reiterating.
I also have two nominations of my own.
Staryu for B
Staryu honestly isn't that bad anymore; Misdreavus no longer threatens to spinblock it, so Staryu is actually pretty reliable at what it does now. That alone should be enough to bump it up a bit because it no longer needs support to accomplish a support niche (although it is a valuable support niche that was worth supporting), but it has a decent place on both offensive and defensive teams. On offensive teams, it reaches the coveted 19 Speed tier; in conjunction with its excellent coverage options and good Special Attack, Staryu is able to pose as a solid sweeper and significant offensive threat in addition to providing Rapid Spin support. On defensive teams, it is the only Rapid Spinner that has access to reliable recovery; this is huge, because defensive teams absolutely hate hazards on their side of the field, but running Defog prolongs the match unnecessarily and sometimes dangerously by forcing the defensive team's hazards to be reapplied. An EV spread of 116 HP/156 Def/236 Spe allows Staryu to maintain 19 Speed, but also usually avoid the 2HKO from Drilbur's Earthquake and 2HKO in return with Scald, allowing it to serve as a good check and demonstrating that Staryu isn't unforgivably frail.
Drilbur for A+
Rapid Spinners are much more effective without Misdreavus, and Drilbur, being the best Rapid Spinner, has only gotten better since Misdreavus left. Even without Rapid Spin, however, Drilbur is an absolutely phenomenal Pokemon. It is the only relevant offensive Pokemon that utilizes powerful STAB Ground-type moves; a testament to just how threatening Drilbur is would be that teams usually still want to make sure to pack a good Ground resist, solely because Drilbur exists. A +2 Earthquake coming off 18 Attack can be tough to deal with, and it helps that Drilbur's 17 Speed isn't too shabby, either. Drilbur's enormous offensive presence allows it to force plenty of switches, giving it ample opportunity to set up Stealth Rock or Swords Dance, or simply utilize the aforementioned Rapid Spin. Its immense offensive and supporting potential is made even better by how the majority of common attacks fail to OHKO the Eviolite set, and many defensive Pokemon fail to even 2HKO without prior damage, giving it plenty of time to wreak havoc.