Gonna do a personal VR with my
extensive knowledge of the current meta, see how much it agrees with what
Quagg is gonna post. Sorry if reasoning isn't super indepth, but there's a lot of mons.
S rank
Haunter is fine
A+ rank
Pilo is fine
Machoke: A+ to S. Objectively the best or second best mon in the meta depending on your meta takes. It's a great mon on any team and playstyle, has set variety, massive building threat, almost mandates usage. It's very difficult building a team without Choke, provides an insane amount f value in one slot that is worthy of S
A rank
Cors, gloom, and klang are fine.
Galarian Linoone - A to A+. It's the fastest viable unboosted mon in the tier, offers great utility and support, and is the best Haunter revenge killer in the tier. Great pivot, very splashable, can run Tosic Orb too to revenge +2 Tort after chip, for a decent amount of teams it forces Choke or a physdef or spdef wall to tank a knock, softening them up for the likes of Haunter, Wartortle, specs special attackers etc. It's not immediately threatening, but does provide a great deal of support and utility that goes beyond A imo.
A- kinda ass
Fraxure A- to B+. Clefairy being far more viable than it was a few months ago hinders frax viability, and Wartortle being the premier form of setup right now also means it competes with more as a wincon. It's not terrible, but is difficult to fit on a team, especially considering it needs quite a lot of work and support to clean at +1. It's not A- material.
Hattrem A- to A/A+. Definitely needs a rise. It's still one of the premier hazard deterrents, and this new physdef giga drain sets means it has a favourable matchup and can switch in fairly comfortably to every viable hazard setter in the tier except Gcors and charja. It warps gameplay when it comes to hazards, and is a good mon outside of Magic Bounce. The specs set has seen a fall from grace due to an abundance of specially defensive walls, but hatt is still better than A-.
Mareanie A- to B+. Mareanie is just too weak to a lot of the top threats to be a viable defensive wall. If you want a machoke 'check', you'd run Gloom or Gcors. If you want a Haunter or Wartortle check, youd run spdef brionne, klang, rose, maybe even shellos. Tspikes and knock niche is nice, but idt it's worth being a less reliable wall for.
Trapinch A- to B. Yh this things not good. It offers far too little in one slot. NFE is very compressed building wise, you need to cover a lot of threats in 6 slots or atleast have counterplay. Trapinch offers zero real defensive utility, and its not worth putting it on a team for the few things it can trap when you could offensively pressue them in other ways.
Vulpix A A- to B-. Screens Morgrems a better setter, especially with the one-time Twave bail that screens offense sometimes needs.
I think tort is fine at A- for now, but could be decent in A too.
B+
Carkol B+ to A-. Good role compression in one mon, being a haunter check when spdef is also nice, it checks a fairly unique but important set of Pokemon with its typing that not many walls can provide, such as Gloon, Rose, Haunter, Klang etc, while providing hazards, removal (or secondary removal if paired with Hatt). Its a fairly splashable defensive mon that deserves a higher rank than everything else in B+ currently, altho with how bad A- currently looks, its hard to judge B+.
Charja is fine.
Clef is fine, maybe A- but not sure.
Ferroseed B+ to B. The tier just has more valuable defensive Pokemon. It's hard to fit ferro on a team when other Pokemon can fulfill the defensive role you'd use Ferro for more reliably.
Morgrem is fine.
Palpitoad is fine.
Roselia B+ to A- With the recent trend and rise of both offensive and defensive waters, a good grass type like Roselia that can perform both offensive and defensive capabilities while providing a Spiker and Tspikes absorber is super nice. Offensively it can weaken walls like Carkol or Hattrem for other Pokmeon or blow through teams that rely on spdef water as their spdef wall. Defensively, it checks Haunter, the offensive waters, can switch into Toxic etc. Good mon, definitely better than most of current A-
Toge is weird, idk how I feel about that mon in general, i always over/underestimate it in different metas.
Torracat idk, probably B+ to B but I have no real reasoning one way or the other on him, just haven't seen/used him enough to make a call.
B rank
Brionne B to B+ Both offensively and defensively, Brionne is super annoying, especially if your team isn't packing a Grass. Fully spdef resttalk is probs one of the best Haunter checks you're gonna get, while also walling basically every non Grass special attacker in the tier, except for the likes of recovering boosters like Vull, Toge and Duo. It's also really difficult to break on the special side, but most physical attackers in the tier lack reliable recovery, so it's not too difficult to wear down the mons that break brionne. Specs is powerful and annoying to switch into. It's better than B.
Dartrix is fine.
Duosion is fine.
Lampent B to B-. I've never actually seen anyone really use Lampent for quite a while, but it seems outclassed by Haunter as an offensive Ghost, and all the spdef wall prep for Haunter, Tort, and some specs users does not help it at all. Very difficult to fit on a team, and the iter has better special attackers.
Raboot is fine.
B- is also pretty bad, minus seems like a bad rank
Drakloak B- to C. Yh this things p ass now, was decent back in Dyna times, but even though it's the fastest unboosted mon in the tier, it's too trash to make use of that speed.
Farfetch'd G B- to C+. It's outclassed by Machoke on 99% of teams, but still has the unique niche of being a moderately fast (in comp to NFE speed) Fighter with Defog.
Haka is fine.
Munch is bad but fine.
Natu B- to C+. Mostly outclassed by Hattrem. It does have a few unique tools over Hatt, like reliable recovery, two pivot moves etc, but it's just too frail to stand on it's own in the current meta.
Pikachu is fine, maybe B but not sure.
Thwackeys fine
Vullaby B- to B. It's a decent spdef wall and fogger. Does face heavy competition from other Pokemon for those roles, but it can do it in one slot which is nice. It's objectively better than its current B- partners.
Reasoning is probs gonna be shorter for these C rankers. I think a lot of them are relics from a previous meta that don't currently see usage and have no notable niche.
C+
Mudbray is fine
Vulpix C+ to B-. Partially because most of C is quite bad, but sun is also a fairly underexplored playstyle rn, especially with a lot of the common spdef walls being steel, grass or water types. It is heavily mu dependent, but I think it's a viable enough playstyle for it's weather setter to be in the B's
Zweilous C+ to B-. I think zwei is is a better mon than the current C rank stuff. It has a good enough speed tier to be dangerous for most teams and be faster than half a current nfe team. If your team doesn't have a Fairy, CB Hustle attacks (if they hit) are scary. It doesn't have the same spammability as Rufflet did, but it's decent imo
C kinda where it really falls off
Charm is fine.
Corv is fine.
Diglett I suppose is fine
Drilbur is fine.
Honedge C to UR. I don't think Honedge has any useful niche in current meta. Too slow, pretty frail on the special side
Shellos C to B. I love one of UOP's favourites in December is now p solid. Sticky Hold gives it a massively useful niche over any other wall in the tier, being able to keep its Eviolite and negate Trick, which gives it a extra degree of reliability against Haunter if Spdef. It also has really useful utility moves for a wall, Clear Smog, Infestation, Scald, defense and spdef boosting options, reliable recovery etc. It's more prone to status than something like Brionne, but its objectively better than anything else in C and B-
Shelmet is fine.
Sinistea C to UR. Want a Smasher, pick Tort. Want an offensive Ghost, pick Haunt.
Sliggoo is fine.
C- is chill
Kadabra
Machoke
Raboot
Corsola-Galar
Hattrem
Piloswine
Tangela
Thwackey
Klang
Ferroseed
Mareanie
Vullaby
Wartortle
Clefairy
Duosion
Lampent
Roselia
Charjabug
Fraxure
Linoone-Galar
Morgrem
Dartrix
Fletchinder
Gastly
Koffing
Mienfoo
Palpitoad
Drakloak
Hakamo-o
Porygon
Seadra
Slowpoke
Togetic
Torracat
Abra
Brionne
Carkol
Dusclops
Dwebble
Gloom
Krokorok
Lickitung
Zweilous
Charmeleon
Hippopotas
Munchlax
Natu
Vulpix
Drilbur
Farfetch'd-Galar
Mudbray
Sandshrew-Alola
Shellos
Stunky
Vulpix-Alola
Whirlipede
Woobat
Rufflet S -> A-
Gurdurr A -> A-
Haunter A -> A+
Diglett B -> C
Pawniard B -> B+
Cutiefly C -> UR
Dewpider C -> C-
Dottler C -> C-
Frillish C -> UR
Honedge C -> C-
Scraggy C -> UR
Shelmet C -> C+
Remoraid UR -> C+
Boldore UR -> C-
Ponyta UR -> C+
Trapinch - B to B+ / A-: What Trappinch offers to the right offensive teams is invaluable / borderline uncompetitive. It can get rid of a handful of crucial checks and counters depending on if its CB or Eviolite, allowing for Haunter and entry hazard setters to run rampant. It single handedly devalues Klang and Ferroseed as special walls, and puts much more pressure on Piloswine to be the only guranteed Haunter switch in (which already is a mess because of the liklihood of Wisp or even Specs Energy Ball taking it down). Even Linoone-Galar has a heavy opportunity cost of running Evio Taunt, the best of its sets for punishing Haunter / Gors, for its likelihood to be 1HKO'd. It usage has even warranted Hattrem running Protect itself for almost no other viable reason. Surely, Trapinch is worthwile amongst the top tiers, as it warrants an entire strategy that has seen a ton of success with limited to no viable counter play once its in.
Drizzile - UR to C / C+: You know I had to do it to em. Attached below is a spoiler of the set I've been running these past two months. Drizzle only has a few niches but they are very valid on the right teams. It threatens bringing Piloswine down to barely any health (small chance to 1HKO), can 1HKO Haunter with Sucker Punch (25% chance normally; 87% after 1 turn of LO recoil), pivot with U-turn, and lastly 2HKO's Mare with Mudshot. These are the positives and yes, it pretty much stops here outside of the reasonable Torrent situations and nailing slower physical attackers like Machoke, Gurdurr, and Rufflet. The fact of the matter is that the meta is way too focused on physical attackers and walls, so having a midspeed Water-type mixed attacker can actually be a valuable support to some teams. Not to mention that some teams only have 1 or no Water resists, and that once in Torrent range Drizzle can 2HKO Gorsola and 1HKO specs Hatt. It obviously has its competition, but the fact that the tier just lacks special attackers as a whole makes the small niches Drizzle have noteworthy and totally worth ranking.
Corvisquire : C to UR: this is unviable
A to S
New to B 
UR to C-. A Calm Mind Cotton Guard set with Unburden has seen a fair amount of success recently as a effective win condition especially on screens teams.