Good day, fellow humans. I am a first-time contributor to this forum and would like to share my handful of noms. Despite not playing much since the Urshifu meta (though I will definitely play more often since horse just got banned, thank Arceus), so take everything I say with a grain of salt. Nonetheless, after reading these posts (and my own personal logic) I think I have a sufficient amount of knowledge of this metagame, at least enough to contribute to the forum.
The Rises
A+ -> S
They say that the best defense is a good offense, and Cinderace is the walking epitome of that concept. When it comes to offensive and supportive prowess, the Ace has it all. A stellar speed tier, an effective base 174 attack thanks to it's phenomenal ability, a nigh unmatched movepool to compliment Libero, and access to STAB U-Turn + Boots. For an offensive threat especially, the Ace has deceptively high longevity because his Speed and Power force out so many Pokémon that he hardly even gets hit himself. Horse being gone is especially great for him, since he's less hard-pressed to run Sucker Punch and can now freely run his dream set of Pyro Ball, HJK, Gunk Shot and U-Turn without having to worry about getting beaten by a dead horse. He has only 3 relatively consistent defensive checks in Slowbro, Toxapex, and Hippowdon, the former 2 of which get blown away by the absolute meme that is Work Up + Electro Ball. Cinderace is the face of the metagame in my opinion, even more so than Magearna, and this rise is reflective of that.
A+ -> S
This is probably one of my more controversial nominations, and even I'm still a bit shaky on this nomination, but I'll still throw it out there because why the hell not? While still a far cry from it's former glory with the loss of HP Ice and Supersonic Skystrike, Landorus-T still remains as the quintessential glue mon in the history of the competitive environment. Ground-Flying is a phenomenal typing due to its lack of weaknesses and valuable immunity to Ground and Electric, Intimidate is just a massive "fuck you" to almost every physical attacker in the tier, it has a vast movepool and incredibly high Attack. This is an example of a Pokémon who can perform damn near any role and perform it well. Defensive sets have great utility in Knock Off, Toxic, and U-Turn, Scarf sets are still reliable Speed control and can check a ton of shit with Intimidate and its hard-hitting Earthquake, and even lead sets with Rocks, SD, and Explosion are just some examples of its incredible versatility. This would definitely be a low S though, because of the existence of Garchomp who is similarly versatile and a way better offensive rocker and sweeper.
A -> A+
Never before have I seen a Pokemon that combines incredible defensive utility with incredible offensive support as beautifully as the Bro. This mon is just perfect in so many ways. Slowbro's typing and phenomenal stat distribution is capable of singlehandedly checking every physical attacker in the tier bar the offensive Grasses, and frankly this total goober just doesn't fucking die due to having both Slack Off and Regenerator. But above all, the Bro was built to be team player and support a plethora of offensive powerhouses thanks to the godlike synergy of its typing, stats, ability and movepool. Future Sight + Teleport + Regenerator is already a powerful strategy on paper, but coming off a mon with 95/110 physical bulk and base 100 Psychic STAB and you have the perfect enabler. The only reason I'm not nomming him to S is because the Bro folds to special attacks, has exploitable weaknesses, and competition with Toxapex for the role of bulky water on balance team, but Slowbro will always be a staple water of bulky offense thanks to it's impressive momentum generation.
A- -> A
Another defensive Psychic that vastly benefits from horse being gone! Glowking is if Slowbro decided to become a special wall and decided to hog all of the offensive prowess it used to provide for its team. Glowking's Assault Vest set combined with its bulk and power is capable of being an incredible special sponge that also forces shit out with its colorful movepool that allows it to pick and choose its checks. Future Sight and Sludge Bomb are givens due to the former's supportive capabilities and the latter's poison chance, but Flamethrower provides coverage against Steels, Scald can threaten physical attackers, Earthquake can be used to kill Heatran and other Fires, and even more niche options exist. Ghost types won't be as much of an issue either thanks to Gengar and Aegislash being unreliable switchins. Glowking will always remain relevant in the metagame thanks to being a phenomenal special wall with slim to no safe switchins.
A- -> A
B -> A-
C+ -> B+
C -> B-
The reasons for the rise of the undead should be clear as day. With horse no longer mandating a Ghost resist or providing competition, each of these Ghosts will have a second chance to shine. Dragapult's unmatched Speed tier and valuable utility in Thunder Wave, Will-o-Wisp, and U-Turn, allow it to shine as an offensive pivot again. Aegislash will return to be the powerful and versatile wallbreaker it once was, and its movepool allows it to bypass its weaknesses. Shadow Sneak patches up his speed issues, and Close Combat and Toxic can be used to bypass traditional checks, though his weaknesses to two of the best offensive moves in Knock Off and Earthquake hold it back from being higher.. Gengar will also rise to absolutely sit on Blissey and set up Nasty Plot to break shit, not to mention its ability to act as a revenge killer with Scarf. Blacephalon is definitely the weakest of the bunch, considering Dark types wall it harder than the other 3, though it is still very powerful and never something you should ignore due to its snowballing ability.
B+ -> A-
Hippowdon is one of the best checks to both Cinderace and Magearna, the 2 biggest threats in this metagame, so it should come as no surprise that this sand hippo should rise alongside. Sand Stream is a very useful ability on the defensive end to chip the opposition, and the sand will stay for a while considering Hippo's fantastic bulk and great defensive typing. Part of what makes Hippo unique is its access to Whirlwind, completely shutting down any form of the notorious Dual Dance Magearna. Outside of checking the top 2, Hippowdon has great synergy with many other popular walls and support mons such as Toxapex, Corviknight, and Ferrothorn, so he can somewhat easily find a place on balance builds.
His great utility in Sand Stream, Whirlwind, Toxic and Stealth Rock always make him an annoyance to face, and being as good as he is versus top tier offensive threats, he should definitely rise one subrank.
B+ -> A-
Kyurem is one of the scariest balance breakers around due to his insane power, coverage, and versatility. Specs sets are borderline unwallable, albeit prediction reliant, because of the threats of Freeze Dry and Earth Power blasting past traditional checks in Water and Steel types. Sub Roost sets are also significant annoyances for more passive teams, easily being able to set up a Substitute against Toxapex, Slowbro, Blissey, and more without getting statused. I'm not a huge fan of Dragon Dance sets because of how easy they are to check with Ice Resists. Kyurem is also slightly matchup-dependent as well, since he doesn't fare too well against offense due to his mediocre defensive typing and 95 Speed, but vs balance builds is where Kyurem gets to absolutely shine.
The Drops
A+ -> A
Ever since Urshifu left the tier, Clefable is no longer as necessary as she once was. Her bulk is relatively mediocre and leaves her easily overwhelmed, especially when she's responsible for checking multiple Pokémon throughout the game. She's still a utility queen and is easy to fit on teams, however she's not as centralizing as she once was.
A+ -> A
Melmetal gets royally fucked by contact punishment due to Double Iron Bash being a multi-hit move, and the prominence of Rocky Helmet Pex, Slowbro, Hippo, and Tangrowth along with Zapdos, Ferrothorn, and Garchomp really doesn't do him any favors. He's also slow as shit and finds himself having to choose between defensive utility or all-out power. Magearna also outclasses him as a bulky offensive Steel, so maybe he'll find a more defined niche once she leaves the tier.
A -> A-
Drill has also had a significant dropoff in usage since its glory days preDLC2. His lead set is almost always outclassed by Landorus-T, and his Mold Breaker support set is difficult to fit on teams due to his lackluster speed tier and other offensive Grounds like Garchomp being much better as an offensive rocker. Sand Rush sets are still threatening sweepers, however it still has a plethora of checks that must be significantly weakened before he can make much progress. Drill is a good mon, but most teams just don't have the room for him.
A -> A-
I don't anticipate Mandibuzz to drop too far considering the Ghosts are on the rise and Mandibuzz is actually capable of beating all of them. However, this is the only reason to use Mandibuzz over fellow defoggers like Corviknight and Zapdos, so it's only really useful for role compressionif you really need a Ghost resist.
A -> B+
Fini seriously does not appreciate current metagame trends and loses to common threats such as Cinderace, Magearna, Rillaboom, Zapdos, and Nidoking. It still checks a decent amount of shit, but it finds itself overwhelmed by its lack of recovery outside of leftovers. I don't see it living up to Pex or Bro in this metagame at all, and it should drop as a result.
A- -> B
This flaming rubber chicken lost its niche since Pheromosa left the tier, and simply doesn't live up to Zapdos in most circumstances credits to his inferior typing. This mon absolutely hates having its boots removed, and this severly hampers its ability to check threats such as Rillaboom and Kartana. Not that great at checking a ton really anymore.
A- -> B
Why is this guy so high? What does he check that Slowbro and Glowking can't besides Nidoking? The Water-Psychic typing is much better fit for walling Physical Threats, and Psychic-Poison is a better type in this meta for walling the special threats. Only use this if you want a more aggressive Blissey or want to use Glowking but really want Teleport.
A- -> B+
Tyranitar is sadly not that useful outside of checking Ghosts and being a solid special sponge and sand setter in general. He's left with a very awkward typing and lackluster power that doesn't really help him check that much.