Since we are now a few events into the regulation, I would like to drop my tier list (not ordered within tiers).
View attachment 636207
Explanation:
Starting from the bottom,

is never and has never really seen any play, as its fellow winged friend

is way better.

is just unfortunate, could be in the C Tier. This Pokemon is a physical attack that doesn't have to worry about Intimidate, thanks to the Full Metal Body ability. This is good, until you realize that

is still scary.

does get Wide Guard, but you might want a Assault Vest to patch up that surprisingly low 89 Special Defense. This Pokemon's attack is also only 137, but with no way to boost that, it can be underwhelming. Hard loses to

as well, with absolutely no coverage to beat it, beside Tera. Now, you want Tera Fire to block burn, but then

comes along. Tera Grass/Water seems good, yet you then get hit really hard by

's teammates, like Flare Blitz

, Moonblast

, and Thunderclap

. Just something that needs that one little buff to be a really good Pokemon. Although

is not super powerful, its bulk doesn't make up for up, unlike

.

is next, and it's here for a reason. It carries no truly good physical Ice STAB, outside of the gimmicky Loaded Dice sets with Icicle Spear, Scale Shot, Protect and DDance. And then, the big ugly cat known as

trampled you with Intimidate. "Tera Ice Tera Blast" you may say, alongside the Clear Amulet item, but 1: Tera is not really doing much but giving you STAB and 2: Ice? Just use the other form (not the base form please).
Next up,

. This Pokemon is a physical attacker, with better attack than

! Clear Amulet here. Good physical Electric STAB is nice, but it has really no good physical dragon moves, as it can't really run Outrage (unreliable), Dragon Claw is weak, and Scale Shot? Really. Physical Dragon moves are just kind of underwhelming. Plus,

exists. Even

works, while giving you another option like

and

.
Let's pick up the pace, shall we? These are the rest of the D Tier Pokemon.

is just not strong enough. Bulky Ghost?

. Strong Ghost?

.

is a little stronger, but the same thing prevails. Better ghosts and better dragons. Plain old

is just outclassed by his past, original variant. Finally, the notorious

. Outclassed as hell.
C Tier
The non-crowned variant of

is now here, with the added bonus of longevity items, like Leftovers or Pinch Berries. Also drops weaknesses to

and

. Obviously, losing loads of resists and gaining Fairy vulnerability is scary, but not as bad as the D Tier Pokemon.

is here, above

. Hear me out. This guy has way more attack, actually making use of it, with a nice Trick Room speed stat. He has more Defense and Special Defense than his non-corrupted version of himself, so that's nice. Also, Photon Geyser becomes a physical attack if the user has more attack than special attack, kind of like Tera Blast. Better Psychic STAB and more attack makes this Pokemon a C Tier.
Next is plain old

, which yet again loses power and the best type combination in the game, but gets to hold the beloved upon physical restricted Pokemon, Clear Amulet. This allows Racism to just demolish:incineoar:with the commonly run Sacred Sword or even Close Combat.
Here is

, and it is definitely better than its sibling. This is because it has good Ice and Dragon STAB with Draco Meteor, Blizzard, Ice Beam and Dragon Pulse, which isn't affected by Intimidate. Only good on Snow Teams, yet the premier Pokemon there.

is ending off the Tao Trio with a bang. This Special Attack that isn't hurt by Intimidate allows it to deal loads of Fire+Dragon damage, even under sun. This Pokemon is kind of slow, but not slow enough for Trick Room. If you are considering Iron Ball, don't talk to me.
Both forms of

are here, boasting the same thing. The reason regular

is lower than it's counterpart is that Telepathy is really good on

with Earthquake no longer being a constant threat.

was seen next to

back in Generation 8, but now it must settle for partners such as

and

which are good, but not anything close to the Ice Riding Behemoth.
Here is my beloved

. This guy is really good at Trick Room and damage. Here, I even have a team!
https://pokepast.es/0532a691d8a03a58 He also works with Tailwind.
We'll cover these two together, as they mesh pretty well. First,

. My guy is a regenerator TANK good damage and burn support in Sacred Fire, not to mention Brave Bird and slotting in really nice into pivoting slow cores alongside U-Turn Rillaboom, U-Turn Urshifu and Parting Shit Incineroar. Its Special Defense allows you to invest into other stats, but being weak to electric,

ain't going to sugarcoat it. You forced to Clear Amulet. Now is the really bulky

, just like its friend.

and

share the same HP and Special Defense, yet

has more Speed and Defense, but

has more Special Attack (talk about useless) and Attack. One does more damage, but one just sits there with Calm Mind and Tailwind boosts.
B Tier
Getting into notable legends, we start with

. A defensive Pokemon with a offensive typing, kind of annoying with your two quad weaknesses to ghost and dark, but under Trick Room, you beat

and

, and you beat

when next to

or

, which you could then slap Expanding Force to wreck any Fighting/Poison type. Shadow Shield is literally Multiscale, and you then live everything (when at full HP).

, with its kind of good speed, can even utilize Tailwind. This Pokemon not only gets Trick Room and Tailwind, but Wide Guard as well! Really good, but not as good as the rest of the Pokemon.
Here is the mighty (and underrated)

. This guy literally shuts down any weather by just existing, destroying

and

and

in the doing, not to mention

and

. I've seen some Choice Band sets running Extreme Speed with Tera Normal, with powerful Dragon Ascents as well. It is run alongside

for extra damage. I think that Clear Amulet

is the way to go, dropping Dragon STAB for Protect, running SD, Tera Normal ESpeed, Protect and Dragon Ascent. This is just so powerful and underrated and it's insane.
The last Pokemon in the B Tier is

. I know, I know. "Why?" You may ask. Well,

. This Pokemon isn't that frail, stronger, and has a better typing. It is even a lot faster. Has a lot better synergy with

as well, with both pressing loads offensive pressure on each other's weaknesses. This doesn't mean

is bad. It still hits super hard and has the bulk. It can run SD with Blades, but I have tried many sets, and I found a supportive set running Protect, Tera Fairy, Wisp, Dragon Claw (let me cook) and Helping Hand, with any item really. This Groudon sits next to Trick Room Pokemon and either A) Does damage B) Negates physical damage C) Powers Allies D) Protects or E) Just is useless. Yeah, use SD sets.
A Tier
Here, we start it off with

. Now, I wouldn't have said this a couple of years ago, but this Pokemon is great. With Body Press, it shreds through even resists. Its obscene bulk allows it to take almost any hit, while being crippled by burn. It even has decent attack, hitting hard with STAB Behemoth Bashes. No item is sad, but it is definitely worth it.

destroys the likes of

,

,

and more. Losing to Ghosts is sad, but Dark type partners such as

or

are really good.

beats

and makes

super bulky on the special side. Overall a super powerful Pokemon that got the one thing it needed.
Now we have reached the new legendary in

. This little cutie gets Multiscale, which is just so good as we've seen. With some bulk, Calm Mind sets can set up and sweep next to helpful partners like

and

. A set picking up is Choice Specs

. This set either Terastilizes and nukes with spread Tera Starstorms, picks up a free KO on non-resists with Hyper Beam, or uses niche coverage that it rarely presses like Earth Power or Dark Pulse. Tera is needed for this Pokemon to function, but it gets a power spike and more health and bulk, which is good. This limitation definitely keeps

from the S Tier.
Next up:

. This amazing sun setter can abuse it loads thanks to its ability, alongside Tera Fire Flare Blitz shredding through literally everything. Collision Course is just so strong with the boosts, and SD sets prove that. Dragon STAB isn't even necessary on a Clamulet SD, Blitz, Collision Course and Protect set, with Tera Fire. I've cooked up a Scarf set with the same moves and Tera, but drop SD and Protect for U-Turn and Dragon Claw. This Pokemon also has great offensive synergy with premier sun abuser,

.

hits steels and darks like

and

for

, while that hits the annoying dragons and ghosts in

's way.

is also really good, destroying rain teams (mentioned by Bright Size).
Finally in the A Tier, we have

. I know, I know, "Bro is Washed". No he is not. The almighty Mystic Water sets, with Tailwind and priority blocking with either psychic terrain or Armor Tail,

is dishing out loads. I like Choice Specs, with the same

,

,and

supports.

or

are both good, patching up the

matchup.

can also catch a switch from

, dealing loads of damage with Ice Beam.

even functions under Trick Room, but not as well as

. Rain abusers are running everywhere, with Weather Ball+Thunder

, Electro Shot

, Surging Strikes

, and even niche options like Swift Swim

. I could go on and on, but the point is, bro is not washed.
S Tier (kinda obvious ngl)
First up on the block, the infamous: calyrex shadow:. This Pokemon moves fast, and hits even harder. No wonder it's in the AG tier. Ok, I'm getting sidetracked. This Pokemon has so much flexibility in its sets, with Sash Tera Ghost and Nasty Plot, Choice Scarf EForce and Trick, or even Life Orb, Spell Tag or Choice Specs. Here is a list of

's moves:
Astral Barrage
Calm Mind
Dark Pulse
Draining Kiss
Energy Ball
Expanding Force
Grass Knot
Hex
Nasty Plot
Pollen Puff
Protect
Psychic
Psyshock
Shadow Ball
Imprision
Trick Room
Substitute
Taunt
Will-O-Wisp
Tera Blast
Trick
There are probably more, but you get the idea. This Pokemon has a great movepool. Its stats are even better, and its offensive typing is a chef's kiss.

is unmatched in bother the ghost and psychic department.
Here comes the mighty

. With super boosted electric type moves and amazing KOs from Meteors, this monster wrecks. Tera Electric just KOs everything, every Volt Switch, Discharge and Electro Drift. And most people wouldn't know if it wasn't for Rajan Bal winning the first regional of Regulation G. This Pokemon is kind of hard to get accustomed to, with most beginners clicking big moves.

revolves around Volt Switch and momentum.
Almost there! Next is

, with it crushing the ladder in the early days of the single restrict format. This insanely bulky and powerful Trick Room sweeper not only sets it up, but sweeps under it too. Partners include

,

, and

. All to say is that this Pokemon is just so powerful.
Finally,

. Extremely underrated, and so, so powerful with good teammates. Check my post before to see

's true potential. I am also a Zacian Believer.
Let me know if I missed anything