Thought dump woo, noting only changes of two tiers or more
Magearna

from
S ->
A
Gets worse and worse as the metagame develops. Faces competition from Solgaleo, Iron Treads is its nightmare, Gouging Fire and Arceus-Electric are on the rise, Arceus-Dark is a rarer sight. Chien-Pao has to drop again or something similar for Magearna to maintain its S-tier status.
Zacian

from
A+ ->
S+
Tera is broken, Fairy/Ground isn't a type yet for good reason. Dondozo is the only reliable defensive check and Zacian is so easy to slap on a team, whether you're using Balance, Offense, HO. Revenge killers are limited and often require you to trade a potentially crucial defensive Pokemon.
Terapagos

from
A+ ->
B+
Pretty much can't spin and can't sweep against a team with the second best Pokemon in the tier (Giratina), no offensive Ghosts for its typing to feel valuable, teams with Magearna/Solgaleo or Clodsire also make you feel like you're barely making any progress and many other Pokemon would be doing more.
Alomomola

from
A ->
B
When the turtle falls, so does the fish. Metagame getting faster and its harder to play Balance with Alomomola as well.
Arceus-Electric

from
A- ->
A+
2nd best Arceus IMO, The Calm Mind set's offensive potency is so threatening and is only really forced out by other sweepers that outdamage it like Gouging Fire. Arceus-Dark also just feels worse with omnipresent Zacian, so it doesn't have as much competition. Also just straight up doesn't care about any incoming speed control at a moderate health and +1. Neutral Judgement vs Magearna and Solgaleo means that they can never keep you in check for long, especially if the Magearna is Thunder Wave.
Gouging Fire

from
B ->
A
Speaking of Gouging Fire, this guy is busted. Dragon Dance takes after Dragonceus and has limited checks, especially in Sun. One of the few Pokemon that stands up to Arceus-Electric, and can use a lot of the tiers defensive staples (Magearna, Solgaleo, Iron Treads, Mandibuzz, and Giratina in some circumstances) as set up fodder. It does struggle into many revenge killers, especially when it ends up hurting itself with recoil or lock in depending on which STAB its using.
Moltres

from
B ->
A
Best Flying-type goes a long way, switches into Landorus, is a fake Zacian check, and can punish a lot of physical stuff with Flame Body. Roar is excellent for what it wants to do, and can U-turn itself to keep momentum. It can also run Will-O-Wisp if it wishes to. Can also be useful as a one-time check to Pokemon like physical Arceus-Poison, Urshifu, Roaring Moon, and Gouging Fire because of its good bulk and utility.
Zamazenta-C

from
B ->
C
You guys need to stop pretending its good...It cant make progress itself with Giratina everywhere, or just Arceus-Poison, Moltres, or even Landorus who deny a sweep. You can slow pivot speed control like Deoxys, Chi-Yu, the worse Landorus, etc and that also shuts down its sweep. I've heard of Sedge sets to lure in Moltres but that's both inconsistent and often means you're missing one of Iron Defense or Roar, so you either check nothing or sweep nothing.
It's not like Zamazenta can make up for this with defensive utility either, it can check Arceus-Dark and Arceus-Ice (barring Tera Ghost) but your teamslot is so much better used on something else, especially when Zacian and a better Steel-type are both near auto includes on teams. It can be used as a one-time check to Pokemon like Poisonceus or Gouging Fire but the incredible inconsistensy is so off putting. It has a niche and can be ranked, but the niche is far too specific to be ranked alongside everything else. No wonder it has a total of 5 whole uses in UUbersPL
Solgaleo

from
B- ->
A
Who knew, when Chien-Pao and Dragonceus get banned, Solgaleo gets back on top? Phasing, recovery, fantastic bulk, pivoting, the Pokemon has it all. Can make an argument for being better than Magearna due to its sheer bulk, having great odds of surviving +3 Tera Blast Ground from Zacian and two Palkia-O Fire Blasts depending on what Solgaleo invests in.
Urshifu-Rapid-Strike

from
B- ->
A-
Very good Choice Scarfer right now, revenge kills Tera Ground Zacian, one of the better speed control into Gouging Fire forcing an Outrage, can pivot to keep momentum. Overall a great Pokemon with good uses and doesn't deserve its ridiculously low current rank.
Mandibuzz

from
C+ ->
B+
Probably the most reliable answer to both Deoxys and Landorus, can pivot, has hazard removal, and Knock Off/Toxic for progress making. Takes 2 Palkia-O Hydro Pumps which really showcases its bulk.
Dondozo

from
C+ ->
B+
The sole reliable Zacian check already gives it a good rep, but Its also good at sitting infront of Physical Arceus, Gouging fire, Roaring Moon, Urshifu, Palafin, yeah every physical attacker not named Ursaluna. It can seem awkward but I think Dondozo also works well on Balance just to keep it alive when facing the many tera sweepers.
Latios

from
C ->
A-
Silly shitmon turned goat. Choice Scarf is great speed control that threatens Gouging Fire and gives an offensive check to Landorus, which is always valuable. Still hits Terad Zacian hard and can Trick to ruin offensive and defensive Pokemon alike. Calm Mind also feels nice on Screens and Sun, since with Tera it can steal some games, and can Recover off damage when switching into attacks like Landorus Sludge Wave.
Walking Wake

from
C ->
B+
Sun is quite good right now with a bunch of offensive pressure, abusing Gouging Fire and worrying less about Zacian with their Walking Wake. Fire- and Water-resists remain scarce and fodder to complimentory Dragon STAB. Its not even weak to Landorus when stacking so many offensive threats because Latios has got you covered.
Ninetales

from
UR ->
B
Better than Torkoal because of Hypnosis, Encore, and Healing Wish all working out so well. Otherwise just see what I said about Walking Wake.
Hatterene

from
C+ ->
B+
Almost mandatory on Sun and can fit on more, see Walking Wake.
Quagsire

from
C- ->
C+
Inconsistent Dondozo with Spikes and Toxic. Trailblaze Zacian cooks you but its quite rare, and it can take on physical Arceus decently well. I do think Dondozo is often the better pick because it does so much more defensively, even when it doesn't make any progress itself.
Iron Bundle

from
NEW ->
B+
Specs and Lorb are the only two sets, I would rather fist fight Arceus than rely on Boots Bundle. Water/Ice is good coverage and its tough to wall, nonetheless SpD Solgaleo takes Lorb Iron Bundle well, and Choice Specs can get its pp drain and acts similar to Scarf Chi-Yu, except it doesnt work as speed control. Encore is a neat tool that punishes set up and defensive Pokemon. My biggest issue with this Pokemon though is that it feels impossible to come in. It dies to everything but isnt like Deoxys where it can outspeed ohko everything and get entry points through that.
Iron Treads

from
NEW ->
B
Rocks pivot that owns Magearna is a treasure. Giratina limits how much Treads can spin though, and Steels are stacked. Not much to say otherwise honestly.