Has been a long time since I made some nominations, so here goes-
RISES -

: S
I agree with the above sentiments and also support this rise. The only very slight doubt in my mind is due to Hurricane's very dodgy accuracy, missing one at an unfortunate time can end all those amazing attributes like that but it is good to the point that despite this major flaw, it is still deserving of S tier.

: S or at least A+
Okay this one might seem like a stretch but seriously this thing is amazing. It's specs set is absolutely tearing the tier up. Ghost resists are notorious for being extremely scarce and with it's immense speed, only beaten by Zeraora and Scarfers above 75, Pult takes full advantage of that fact. Also unlike the ghost horse, it has coverage or just plain good ol' U-turn to beat even Blissey and Mandibuzz. Specs is amazing on it's own but it has another incredible set in boots Twave which funnily enough, somewhat plays like baby Torn T, just making progress with Twave, u turning out of bad matchups and later breaking with boosted hexes. While it does lack Regen, It also stays alive forever because it takes no hazards and never gets hit due to it's ridiculous speed. So that comparison is something to think about. This set also makes full use of it's deceptively good defensive typing and decent bulk, checking things like Volc, Urshifu R, Keldeo, Slowbro, Venu, Tran etc. at least once. There are other sets like DD Sub or Weakness Policy DD which can situationally even end entire games and flex it's physical stab more. This thing is at absolute WORST top 5 mons in the tier and some may even rank it upto top 3 but it's tiering doesn't reflect that currently. It should at the very least be A+. I lean towards S but I think A+ would be more acceptable by the community.

: A+
This thing is an absolute unit. Specs set is average but the set that really amazing is Boots with Roost. The main selling point of Koko imo is it's unparalleled defensive utility for an offensive mon in that it is an offensive yet very sturdy check to Torn T and Zapdos in particular. While the former can carry Sludge Wave or knock off and both can toxic, it still can hold off a majority of sets and it still survives even max sp atk Sludge Wave from former from full. Koko is also not nearly as crippled by knock off as other checks like Zapdos. While this is it's main utility it also checks either stab from +2 Lucha and banded Galardos, it survives +2 Ice shard from LO Weavile which is on the rise( more on that later) and +2 sucker from Bish, it stops any Corvi set up set in it's tracks, it checks Zeraora, Hydreigon, Twave Hex Pult, fini, and can switch into either kanto slow twins and Mandi just by it's typing and access to roost alone . Aside from this amazing defensive role, it fits the role of team's speed control just missing out on Pult and Zeraora, gives terrain control and can even play like extremely fast boots users with pivot moves that have become so common place this gen, just pivoting around, firing off hits, never being worn down and outlasting all counters (This description ironically again reminds of Torn T but it is honestly surprising to see how many mons can play like it just because of speed, boots and pivot moves (and also reliable recovery in Koko' case) ). It's decently strong too with the terrain boost, once the ground types and Ferro are sufficiently weakened, it can just overwhelm the opposing team with it's aforementioned longevity, speed and power. Unlike Regieleki, It honestly isn't extremely bad against grounds either because it can still do all it's above roles and just uturn out of all the non scarfed ground types, heck, chomp is even 2HKOed by Dazzling and Lando, Pert are chipped down too. Ferro, Nido and Exca are it's biggest hindrances because they wall it's dual stab and are not mons you want coming in for free but honestly it still doesn't do very poorly just by it's access to uturn and infact can even bait them in. Despite, this drawback, It just brings a lot of good traits to the table and generally still does performs its role and deserves A+ rank.
(Side note - It's screens set is good too and there is some potential of experimentation with taunt, toxic, nature's madness and volt switch on the boots set but the standard boots set is just so reliable and easy to use that there is really no need to try to change it.)

: A+
This right here is a mon that has literally benefitted from EVERY SINGLE ban since the onset of Crown Tundra and banning of Cind and Mag were no exceptions either. There is really nothing too flashy to talk about this mon. It's standard set just has amazing defensive utility and is arguably the best defogger while being a great pivot. It checks the biggest names in the tier such as - Rillaboom (which seems to break through everything else with knock off and uturn), scarfed Kart, Lele (Also notorious for killing everything if it connects Focus Blasts), Lando T, Torn T and Chomp. While not as omnipresent, checking Melly, Exca, Dnite, etc. is also nice. It can also PP stall defensive mons with pressure like Ferro, Toxa, Clef, etc. and can even pressure stall Kyurem and Urshifu R 1v1. This is just an incredible glue mon that checks so many of the biggest threats around. This mon has overtaken the other birds save Torn and Lando because of it's not nearly as crippled by knock off like the other birds. We have been seeing teams such as Corvi offense and the huge uptake in the usage of Zone in SPLs is a testament to it's affect as well. It is another tier defining mon and should be A+.

: A+
I read some of the above posts and agree with the point people prior to me made about Rilla. Some points that I would like to reiterate are that it enjoyed the bans of the bunnies. It can force progress and potentially break through almost anything with Knock off (being especially devastating for the flying types) and U-turn , it can superpower Ferro and Tran, Glide also is the single most ridiculous move allowing it to revenge just about everything. It has had a huge impact on tier where all teams now accommodate for it by running multiple grass resists. It gives terrain control and arguably the best one for a team at that, making things like Tran and Pex so much more resilient and even helping boots users like Pult and Zeraora. It has great natural bulk which is augmented by it's own passive healing. It pairs extremely well with Zone which removes Corvi and Ferro, former being it's single best check and most definitely the team's most reliable answer to Rilla and the later being used to chip Rilla down. It is a tier defining beast to the point that sometimes people run High Horsepower on their ground types despite not packing one themselves. This is with 3 other terrain mons in the tier. It also is an easy A+ tier.

: B+
This thing has seen a huge uptake in usage since the Mag ban and for good reason. This thing absolutely shellacs balance builds. After SD. it even OHKOes max max Corvi after rocks more than 90% of time with LO Triple Axel. It OHKOes common revenge killers like Rilla,+1 defense Lucha, Regieleki, Pult with +2 LO Shard and Zeraora and Koko need a bit of chip to be put in shard range. It's speed tier is also blistering fast. Another set that is equally good if not more is Banded. It gives it more breathing room to chip down it's checks like Fini, Melly etc. (Incidentally the usage of both of these dropping helps it as well). while also being able to fit icicle crash as a 4th move to avoid RH, static and all those annoying things. It has very minimal defensive use too. It's spdef is actually decent so it can take 2 shadow balls from specs pult and one ice beam from specs kyurem with rocks up which is more than I expected from it before running the calc. With pickpocket it can punish knock off too which is ridiculously difficult to do in this meta game. Honestly, these are just side notes, it's main claim to fame is it's strong offense. Any team without Pex has a reason to fear it as an off beat but dangerous offensive threat.

: B
This mon is such a great pick in the current meta game. It is one of the best defog abusers and teams that rely on Lando T, Brave Bird Corvi to check physical attackers are in for a rude awakening. We have recently been seeing Banded to go all in as a defog punisher to just get an OHKO in return. This mon was put in C tier in the first place because Urshifu S completely invalidated it and Mag, Spec and Cind were tough for it. Now with those mons banned, it does deserve a rise to reflect it's increased viability.

:B-
This is another defog abuser. I don't think this is a splashable mon and is fundamentally flawed in that defog abuse strategy because all the birds can nuke it on the switch with their flying moves and zapdos kanto can survive and kill it even if it came in on defog. But C+ is still way too low for it. It completely dominates the omnipresent Lando T and outside of Zapdos, there are really not too many switch ins to this. I mentioned Koko earlier but it can OHKO Koko with banded stomping tantrum if it predicts right. Sub bulk up set is also amazing on webs. It is an effective nuke and does deserve B-.
DROPS -

: C+
I am a huge Kommo O fan and have really tried every conceivable set to try to make it work in OU and sadly it just doesn't. I have tried offensive Bulk up, DD, offensive SD Scale Shot, Clangorus Soul, Defensive Body Press, Taunt rocks, defensive SD with wish support, Mixed attacker with rocks, taunt defensive bulk up, and belly drum. It is physical offensive sets are stopped by every bird, lando, clef, fini, pex, hippo, slowbro, all choice scarfers etc. It is just a much, much worse Chomp. It's defensive sets just don't accomplish anything. It used to be good against rain but then they started running hurricanes. Toxic and knock off are omnipresent, both of which are bad news for it. Even if walls something, it just gets whittled down while making zero progress itself. Special offensive sets are also suffer from lackluster damage output. The best bet Kommo o has is to cheese for wins with Sub Salac Belly Drum but it simply can't pick any move with drain punch. If it picks T Punch, then it gets revenged by Pult and if it picks EQ, it gets stone walled by Togekiss, Lando, Torn and Zapdos, if it picks Ice Punch it get walled by Slowbro and Pex. Not to mention, Phys def Clef survives any +6 attack save Poison Jab and Iron Head. This all is relevant IF it get's it's set up in the first place and even if it does, still every single Scarfer in the tier is faster then it. I implore the council to just drop Kommo o as soon as possible and just take away the false hope the VR gives me on seeing Kommo o in B.

:B+
For a first few days after DLC 2, Fini was considered the best Tapu for it's new Calm Mind draining kiss set but slowly the meta game has been turning hostile to it. Every single grass mon in the tier stops this set in its tracks also giving Kart and Rilla free attacks coming off of pivots is also not ideal. Slowking Galar rose a lot in usage and it also completely stuffs that set. Mons Like Lele, Kyurem, Chomp, Pult can just overwhelm Fini and leave it too weak to set up later if not outright KO it. Outside of this set it is not A- good. It is overshadowed by Slow twins, Pex as water types defensive mons, Corvi, Zapdos, Torn T as defoggers and Heatran as a taunt user. There is no Spikes Greninja for it to check and defog on. Even something like Weavile, whose stabs Fini resists is better checked by Pex due to it's absurd longevity. It still is decent but just doesn't seem to be on the same level as Lele and Kart.
Edit: The Hydrei nom, it has been pointed out to me, is completely incorrect and I also see some of those points now. I think it should still be A- and not A but I am simply not the best person to make a nom for that right now. I NO LONGER am nominating Hydrei to drop.