I got a landslide of noms here folks
Rises•

A > A+: I am a firm believer that Washtom is the best pivot in the tier. Outside of teams with Clodsire, Washtom is always forcing progress through status, Hydro, and Wisp. Being one of the few ground immunes in the tier that doubles as a check/soft-check to Tusks, Dnite, Dirge, Gambit, etc. There is no archetype Washtom does not fit in outside of Stall if you pay attention to many teams on ladder or in SPL. Washtom has been proven to have customizable evs for whatever role you want it to fill. A specially defensive pivot for the ghosts and Valiant, a more offensively oriented Washtom, double status, Nasty Plot, Resto Chesto Tera Fairy to completely wall Tusks, your options are endless. Washtom does Washtom things, being annoying asf and bringing in the absolute monsters Gen 9 introduced.

A- > A+: This might seem like a big jump but I’m telling you, Chomp is the best spiker and ground type (not named Tusk ofc) in the tier. The Chain Chomp spike set has blown up as it is the only spiker besides Meow that beats Tusks 1v1 barring Tera shenanigans. Seeing play on numerous spike stacking builds over Ting-Lu. Also punishes Corv with either the Chainchomp special or punishing it with RH + Rough Skin if it tries to do anything besides press Defog or Roost. It has a variety of sets to play with like the aforementioned Chainchomp. There is Tankchomp, SD Tera Water/Dragon, even Scarf. Its typing means it can get multiple layers up againsy Volc, Washtom, Ghold, etc. We pretty much have Ferro 2.0. A wise man once said, no matter the power creep, Chomp will manage to become a top threat. No amount of Lati twins, Fairies, Tapus, Weavile, or Tusks is gonna make Chomp relevant, especially as each gen keeps giving it new toys.

B+ > A-: Meow has been making waves lately, appearing on several styles, archetypes. HO, Spike Stacking, Dark Spam, BO, etc. Its utility is starting to shine through with the limited amount of Knock Off distribution. Knock, Spikes, Taunt, it can always do something for a team. It managed to find a niche in a tier with the other fast dark type cat Chien-Pao (this statement might be dated in a few days). The increased usage of Covert Cloak in response to Garg, Boots in response to the abundance of hazards, and Dozo/Garg/Pex. All three of which Meow can dent heavily with its STABs + a Taunt vs Pex for good measure. Ironically, Meow revels in conjunction with Pao since it lures in its biggest targets and dents its best checks with Knock + U-Turn respectively. Its not a strong wallbreaker meant to rip walls apart, rather it is meant to chip them down for the real wallbrealers to tear up. Dark is a broken offensive typing and soon they will introduce a bunch of dark resists next gen like they introduced a bunch of ghost resists this gen.

B- > B/B+: Worm has been popping off lately, becoming a centerpiece of many HO teams and the substitute of Cyclizar it was meant to be (pun completely intentional). Even if at max it only gets up one or two shed tails a game, any of these shed tails are a game ender, most notably with Espathra. Defensively it checks Dnite, non-fighting stab Tusks, Pao, and Gambit while setting hazards in one slot for offense. A rarity for an offensive staple to fulfill a defensive niche.

C > C+: Just like every generation, Hippo comes back whether it is OU or UU, but we are not at that point yet but it still has a solid niche that sets it from the other grounds and the C rank. Its excellent mixed bulk, access to recovery, and neutrality to fairy sets it apart from Ting-Lu. With Phys D it soft-checks offensive Tusks, Ace, Dnite, etc. With SpD investment it can soft-check Espa, Valiant, Pult, and Dengo. The real reason I’m advocating for a raise is sand. Sand + Spikes is an infamous combination in ADV and now in a tier with more Knock Off, worse hazard control, and more spinblockers, it aids in wearing down those threats, making lefties recovery for nearly a third of the OU tier futile for 5 turns. Garg getting a massive SpD boost under sand makes it even more unkillable. Since Hippo is setting rocks, Garg is free to run Curse or other options.

C > B-: Underrated. I know it is a massive jump but do not sleep on da Zone.
(Exhibit A): Magnet Pull is its bnb. It lost alot of relevant targets, but the three steels it can trap are highly relevant ones. Corv is obvious, Gambit seems unphazed but a Tera Fighting or Ground disposes it quickly. Zone exploits Worm’s shit special bulk and either kills it or removes the possibility of a shed tail. Gambit is alot of team’s check to Meow, ghosts, Pao, and Espa, but with it gone, they can go off. Meow in particular is seeing a spike in usage, justifying a slot for Zone even more.
(Exhibit B): 130 SpA. In the same caliber as Volcanion, with STABs that hit mostly everything neutrally or super effectively. Don’t sleep on this just because Ghold has 3 points higher SpA. Garg, Dozo, Tera Fairy Dirge, Hatt, Pex, and Corv are prime victims for Zon to exploit.
(Exhibit C): Tera expands its capabilities even further. Tera Ground to run through Gambit, Ghold, Treads, and Clod. Tera Fighting for Gambit (again), and Ting-Lu, Tera Fairy cause its Tera Fairy, and Tera Flying as a big F U to Tusks.

D > C: Considering the more offensive nature of the tier, Lokix deserves a bit of respect as it does well in that mu. It has a shitton of flaws. Garbage bulk, several mons have a dual resistance to Bug, rock weakness, relies in LO/Band to support its admittedly decent 103 Atk. Though with big upsides in the meta. Alot of people regardless of skill level Tera defensively. (I.E Tera Gambit or Moon), however Lokix having Tinted Lens + STAB First Impression lets it avoid the 50/50 all together. Its speed tier is great vs Tusks, Ghold, Quaval, and most Volcs, the latter is notable considering it 2HKOs the sample set with Band Leech. With U-Turn it forms a decent voltturn core with stuff like Ace and others. Though most of its niche stems from its mu vs HO, setting it apart from its vast competition. It requires heavy support, which is why it should not go any further, but it has a notable niche that is worth considering a blue moon.
https://replay.pokemonshowdown.com/gen9ou-1796856511
Lokix replay 1 (vs Balance)
https://replay.pokemonshowdown.com/gen9ou-1796861570-zg998312n1h38am2qp8vg16tclj5j5jpw
Lokix replay 2 (vs HO)
Drops•

A > A-: Obviously still good/great but not as splashable as most of the other threats that check even more stuff. Competing for slots is becoming harsher with the overall nature of SV OU. Gambit and Meow seeing higher usage not helping matters for it either. Band Pao OHKOs it after chip and Tera. There is some potential for an offensive TR set, but as of rn, its current ranking doesn’t reflect its status.

A > A-: Though this thing is annoying asf with Tera Flying, Pao being the biggest mon rn hurts its viability by a margin. Being direct competition with it and able to rkill it regardless if it Tera’s or not. Moon’s 4mss is starting to show. It wants EQ for Gambit, it wants Roost for Garg, it wants Taunt to shutdown status attempts from Washtom and Pex, it simply can’t use all these great options at once. Dnite is also rough competition for it. Still a good sweeper that can get setup opportunities off of its many resistances and Tera.

C > UR: Going from nice to harsh here but I’m sorry. What the fuck does this thing do that its competition doesn’t? It has a million competitors for its role. Back in SS its role was either as a wallbreaker with Dark STAB that got up sand or a special wall. Whats wrong with it now? Everything. 95% of the meta has a way to threaten it; this thing has little to no switch-in opportunities. Slow bulky Wallbreakers? Look around you, you got Tusk, Gambit, and Iron Hands. Gambit in particular having way better resistances on top of 5 points higher Atk. Brand new checks in the omnipresent Tusks, Valiant, Ting-Lu, Quaval, and Dozo. Zone doesn’t have this problem since its STABs are better in this landscape and special walls are less prominent than the physical walls of this gen. A special wall with rocks and a ghost resist?
FUCKING GARGANACL. Everything this thing did is either done better by other mons or absolutely gone. Its a slow ass Rock/Dark type, weak to ground/steel/fighting/fairy/water. You can offset those weaknesses with Tera, but are you gonna waste your Tera on Ttar when you have 5 other mons on the team that can use Tera and better? You get my point. Maybe Ttar will regain its OU status like it did last gen through eventual meta shifts and/or Home/DLC, but rn this is the worst Ttar has ever been.

> A/A-: Gren is a great addition to the tier. A special wallbreaker with spammable moves, a spiker that gives zero shits about Tusks/Corv, and threatens a ton of tier staples like Tusks, Ghold, Dirge, Dozo, Garg, and Chomp.
I might make a part 2 post-Pao suspect, but its not an exaggeration to say that a majority of the meta would appreciate Pao being gone.