Shoutouts to @RoiDadidou and his
spreadsheet for easy reference to all the information, and also this
pastebin for formatted base stats and this
pastebin for combined move names and descriptions. Overall the data is still incomplete so far but I'm comfortable starting from here and editing going forward. (Fortunately the full BSTs dropped midway so I was able to make some actual comparisons there. Hopefully they are real.)
POKEMON
Note I won't be going over every mon here, and honestly I don't really have a lot to say on the surface what with how tera might affect the meta, but I think there are some cool additions.
Meowscarada (Grass/Dark) - 76/110/70/81/70/123 (Total: 530): This cool cat is pretty fast but falls short of its competition otherwise.
Skeledirge (Fire/Ghost) - 104/75/100/110/75/66 (Total: 530): Decently slow and relatively bulky and balanced among its Fire/Ghost competition.
Quaquaval (Water/Fighting) - 85/120/80/85/75/85 (Total: 530): Faces tough competition from every side of the stat spread with Arghonaut (slower and bulkier) and Urshifu/Keldeo (stronger in most other stats).
Brambleghast (Grass/Ghost) - 55/115/70/80/70/90 (Total: 480): This tumbleweed chose Speed, and so it is worse than Necturna everywhere else. Goodbye.
Dudunsparce (Normal) - 125/100/80/85/75/55 (Total: 520) I think Dudunsparce has some tough competition with classic normals from Snorlax to Ursaluna, but I would rather talk about Dudunsparce than the pigs that it's better than.
Houndstone (Ghost) - 72/101/100/50/97/68 (Total: 488) It's a ghost dog, but physical. Probably not that great but it's a ghost.
Farigiraf (Normal/Psychic) - 120/90/70/110/70/60 (Total: 520) The giraffe is a lot like Dudunsparce but more inclined towards Special Attack. I just noticed they have the same BST.
Dondozo (Water) - 150/100/115/65/65/35 (Total: 530) Big fat catfish. The slowness is nice and the physical stat spread kind of reminds me of Urshifu. It also forms a unique combination with the sushi mon.
Palafin-0 (Water) - 100/70/72/53/62/100 (Total: 457) Not great, but Palafin gets a form change on switchout so that should be a pretty solid choice to pick from the teambuilder...
Palafin-Hero (Water) - 100/160/97/106/87/100 (Total: 650) Or the form could be so powerful it exceeds the BST cap. Oh well.
Arboliva (Grass/Normal) - 78/69/90/125/109/39 (Total: 510) A new slow Grass type. Honestly it's still probably not that great but it's a step closer to the meta.
Bellibolt (Electric) - 109/64/91/103/83/45 (Total: 495) Fat frog. I just put it here because it's slow but you may as well use Mega Ampharos.
Cetitan (Ice) - 170/113/65/45/55/73 (Total: 521) Fat whale. This has really big HP for an ice type though.
Baxcalibur (Dragon/Ice) - 115/145/92/75/86/87 (Total: 600) Our pseudolegendary. Has one of the highest Attack stats among dragons and is still decently bulky, with a handful of weaknesses to make use of. There's always tera too, but that's getting ahead of myself.
Tatsugiri (Dragon/Water) - 68/50/60/120/95/82 (Total: 475) Sushi mon. Nothing special by itself, but its signature ability is supposed to form a unique combination with the catfish.
Flamigo (Flying/Fighting) - 82/115/74/75/64/90 (Total: 500) This is like slower Hawlucha. I only mention this because it has 500 BST and is Flying type and it has a funny name.
Garganacl (Rock) - 100/100/130/45/90/35 (Total: 500) A nice and slow titan of salt, with its only deficiencies being Special Attack and Speed. It kind of pales to Regirock in defenses though, with only having 20 HP over it.
Glimmora (Rock/Poison) - 83/55/90/130/81/86 (Total: 525) Nihilego 2 but not as lopsided.
Great Tusk (Ground/Fighting) - 115/131/131/53/53/87 (Total: 570): Strong physicals and weak specials.
Brute Bonnet (Grass/Dark) - 111/127/99/79/99/55 (Total: 570): Pretty nice slow grass, actually pretty similar to Zarude but without the speed.
Sandy Shocks (Electric/Ground) - 85/81/97/121/85/101 (Total: 570): I'm not sure if Stunfisk is better than this. The weaknesses and resistances seem balanced on the surface with more common weaknesses, so Weakness Policy might be alright.
Scream Tail (Fairy/Psychic) - 115/65/99/65/115/111 (Total: 570): The bulkiest and fastest Fairy/Psychic by far, though it lacks offenses to compensate. I don't know how to feel about this one considering it doesn't even have that many weaknesses to proc WP off of, but the closest comparisons in its type are big special hitters.
Flutter Mane (Ghost/Fairy) - 55/55/55/135/135/135 (Total: 570): Speaking of big special hitters, this is one. It's faster and has more SpD than most ghosts but is definitely more physically frail.
Slither Wing (Bug/Fighting) - 85/135/79/85/105/81 (Total: 570): Kind of a mini Heracross with less Attack/Defense and more Special Attack/Speed. It doesn't really say a lot considering Heracross's main selling point is its raw Attack.
Roaring Moon (Dragon/Dark) - 105/139/71/55/101/119 (Total: 590): It's raw. More speed and physically inclined than special unlike the other Dark/Dragons who have succeeded with Weakness Policy in the past. 139 Attack is pretty big though.
Iron Moth (Fire/Poison) - 80/70/60/140/110/110 (Total: 570): 140 Special Attack is pretty big and Fire/Poison has a lot of resistances but with some common weaknesses as well.
Iron Hands (Fighting/Electric) - 154/140/108/50/68/50 (Total: 570): A rare slow paradox that boasts a healthy HP stat of 154. Could be a fair rival to the physicals of Ursaluna/Glastrier, though noticeably lacking Special Defence in comparison.
Iron Jugulis (Dark/Flying) - 94/80/86/122/80/108 (Total: 570): Galarian Moltres has an edge in Special Defence over Special Attack and Speed but it's pretty balanced.
Iron Thorns (Rock/Electric) - 100/134/110/70/84/72 (Total: 570): It's mostly Tyranitar but worse specially with some extra speed. Maybe you can still make Weakness Policy work.
Iron Bundle (Ice/Water) - 56/80/114/124/60/136 (Total: 570): This chose to focus on Speed, Special Attack, and Defence which is a pretty odd combination. There are other better choices to Weakness Policy with, but the mon is a funny penguin.
Iron Valiant (Fighting/Fairy) - 74/130/90/120/60/116 (Total: 590): Cool mixed power, very Azelf-like. I think it's still a bit frail and vulnerable to weaknesses though.
Ting-Lu - 165/110/130/50/80/45 (Total: 580) - Dark/Ground - Pretty cool new member of the slow and physically bulky/healthy archetype, and could probably pull off Weakness Policy alright with its fair share of weaknesses/resistances/immunities.
Chien-Pao - 80/130/80/90/65/135 (Total: 580) - Dark/Ice - Mostly better than Weavile which isn't saying much.
Wo-Chien - 85/90/100/100/135/70 (Total: 580) - Dark/Grass - The Flower Veil archetype gains a new legendary member, and it has the highest Special Defence of grass types so far and a decent speed stat. Pretty neat.
Chi-Yu - 55/80/80/145/120/100 (Total: 580) - Dark/Fire - Lastly we have a big special hitter that's mostly balanced but kind of dumps HP in the end.
Armarouge - 85/60/100/125/80/75 (Total: 525) - Fire/Psychic - Probably better off with Victini.
Ceruledge - 75/125/80/60/100/85 (Total: 525) - Fire/Ghost - It's another Fire/Ghost, but specializing in the places Skeledirge doesn't.
Toedscruel - 80/70/65/80/120/100 (Total: 515) - Ground/Grass - It's Tentacool but a Grass type. Mega Venusaur basically outclasses it in its main element.
Clodsire - 130/75/60/45/100/20 (Total: 430) - Poison/Ground - 20 speed lol.
Annihilape - 110/115/80/50/90/90 (Total: 535) - Fighting/Ghost - Marshadow but with higher HP and less SpA/Speed. Honestly it's a close one but Marshadow's mixedness should make it more consistent.
Overall this generation looks to have some fun new high BST tools to play with, but in the end it's all about what works for you.
NERFS:
Cresselia lost 10 in both defenses, going down to 120/70/110/75/120/85. Ouch!
Hisuian Zoroark had its stats adjusted to match regular Zoroark, losing SpA and Speed and gaining back HP and Attack.
ABILITIES
I vaguely sorted these by how I can see their viability, though we still need more details on how they will play out for some.
Banned tier:
Earth Eater: Ground absorb. Probably banned for HP restoration.
Seed Sower: Creates Grassy Terrain on hit. This will probably be banned for HP restoration.
Interesting:
Commander: It seems like this is for the sushi dragon to merge with the catfish somehow. Apparently Khu thought this would be very strong in doubles, so I'm interested to see how it works out in practice because there are very little details on it. Of these this is probably more of a gimmick, but I think it could be the next Gulp Missile.
Well-Baked Body: Take no damage from Fire moves and get +2 Defense instead. This is probably better than Flash Fire for a Fire immunity.
Opportunist: Boost the same stats as enemies. This could be pretty funny to copy enemy weakness policies but is more of a passive ability.
Purifying Salt: Makes you immune to status AND halves Ghost move damage. This may be an upgrade over Comatose for that purpose.
Legendary gimmicks:
Orichalcum Pulse: Sets up sun and gives +1 Attack while in sun. An upgrade over Drought and can set up with later paradox abilities for a nice but temporary power boost.
Hadron Engine: Sets up Electric Terrain and likely gives +1 Special Attack while in Electric Terrain, as an upgrade to Electric Surge.
Protosynthesis/Quark Drive: Boosts the highest stat in Sun/Electric Terrain respectively, or if holding Booster Energy. I don't know how good using your partner or item + ability slot for a single boost is or how large it is, but you could have some setup gimmick teams with this for sure, and potentially permanently if it interacts with Desolate Land.
Overall I'm not really sure how to rate these, but they are definitely gimmicks you can set up easily if you want to do so with a team.
Other gimmicky abilities:
Good as Gold: Become immune to enemy status moves. This probably shouldn't include Metronome itself but rather its called move. Honestly Magic Bounce might be mostly better in practice unless facing another bouncer, as it will repel most status moves instead which is usually better.
EDIT: Arrrrgh I just realized that this could potentially block Perish Song right after I thought about it a bit more. This is why I think it's not totally outclassed as being immune to status moves is unique and probably pretty good on its own, it's just that Magic Bounce already exists and is top tier.
Anger Shell: When hit below 50% HP, raise Atk/Spa/Speed and lower Def/SpD by 1, like a mini Shell Smash crossed with Berserk. Not the best boost, but I guess you can count on it to happen in a match if you want to turn the tables and get consecutive hits with a speed change or something.
Tablets/Sword/Vessel/Beads of Ruin: Lowers Atk/Def/SpA/SpD of all other Pokemon except itself, probably affecting your ally as well. I'm not sure how to feel about these abilities exactly, as I can see uses for them but also . I don't think they will trigger Defiant on an ally and Contrary may work but feels like a waste. Still, it's debuffs we didn't have before.
Pretty Niche Move Rolls:
Sharpness: Powers up slicing moves. This sounds pretty niche.
Rocky Payload: Powers up Rock moves. This is pretty niche.
Electromorphosis: Gives Charge (2x damage on Electric moves) when hit by an attack. This is pretty niche to rely on a specific offensive type, but I guess it will always be up.
Wind Rider: Take no damage from wind moves and boost Attack instead, including Tailwind. This is better than Wind Power but still pretty niche.
Thermal Exchange: Boosts attack when hit by a fire move and cannot be burned. This is an upgrade to Magma Armor which is still pretty niche.
Cud Chew: After eating a berry you can eat it again at the end of next turn. It might have some pretty niche uses like eating a Lum twice (if you get statused 2 turns in a row), but Ripen and Harvest are probably better in the long term.
Redundant/Outclassed:
Wind Power: Activates Charge when hit by wind moves, including Tailwind. This is like worse Electromorphosis in every case but Tailwind, and at that point you just have Charge to show for it.
Armor Tail: Just a Dazzling/Queenly Majesty clone.
Lingering Aroma: Mummy clone.
Mycelium Might: Always act "more slowly" when using status moves, but ignore abilities with them. You may as well just run Mold Breaker from what I understand to always ignore abilities with every move and not act slower.
Costar: Copies ally stat changes on entering battle. This is probably pointless at worst and redundant at best like if you want to copy Intrepid Sword, but at that point you can just run it yourself.
Useless:
Zero to Hero: The dolphin becomes a hero on switchout so it's not going to trigger, but you can probably choose hero form dolphin anyway like Wishiwashi. (mid-EDIT: Alas, Palafin-Hero has 650 BST so it will never see the light of day.)
Toxic Debris: Toxic Spikes are useless.
Supreme Overlord: Pretty useless if it only takes effect on entering battle.
Old edited abilities:
Protean and Libero can probably be unbanned since it only works once per switch (the whole battle) now, and your one type change is going to be spent turning into Metronome's Normal type first.
Battle Bond may just be boosted Atk/SpA/Spe on a kill instead of a form change based on description changes, which may be freeable.
Snow Warning causes snow now which increases defense for Ice types, and Hail is replaced by snow. We can probably free Snow Warning if it doesn't do passive damage anymore.
Intrepid Sword and Dauntless Shield now only activate once per battle. Not a big deal but I wonder how that interacts with Skill Swap.
MOVES
As of writing we don't have the comprehensive move data for what can actually be used and called via Metronome in the game, but I'll go over all the move descriptions briefly because they all have some kind of neat effect. Hopefully Metronome is still usable even without most of its natural users, and I also hope more moves are added to the Metronome use flag compared to Gen 8 which excluded half the new moves for some reason, because it's nice to see some more variety.
Legends Arceus moves have gotten reworks for the modern day and they have various fun effects, some more relevant than others.
Dire Claw is a +crit move with a chance to inflict poison, paralysis, or sleep.
Psyshield Bash boosts defense on hit.
Mystical Power boosts SpA on hit.
Springtide Storm may lower attack.
Raging Fury is a Fire-type Outrage.
Wave Crash is a Water-type Double-Edge.
Chloroblast may be a Grass-type Steel Beam.
Victory Dance is a physical Quiver Dance.
Headlong Rush is a Ground-type Close Combat.
Esper Wing has +crit and boosts speed.
Bitter Malice lowers attack on hit.
Shelter is a +2 Defense boost.
Triple Arrows has +crit, and can lower defense or flinch.
Infernal Parade is Hex but with a burn chance.
Ceaseless Edge has +crit and leaves spikes.
Bleakwind Storm can lower speed.
Wildbolt Storm can paralyze.
Sandsear Storm can burn.
Lunar Blessing is like Jungle Healing where it can restore HP and status for the user and ally. This may be our first ally healing move, but with gamefreak's track record I don't expect much.
Take Heart is Refresh + Calm Mind.
Now we have new moves. A lot of these are signatures so they could go either way with usability.
Tera Blast has the Photon Geyser adaptive damage effect and also changes type when you Terastallize.
Axe Kick sounds like a Hi Jump Kick variant that can confuse.
Last Respects has more power with more defeated allies, so it probably won't get too crazy in a 2v2 environment.
Lumina Crash debuffs SpD by 2 on hit.
Order Up attacks and boosts a stat if the user has sushi in its mouth, so I doubt it is callable.
Spicy Extract boosts the target's Attack by 2 but also lowers its Defense by 2. Pretty risky.
Spin Out lowers the user's speed by 2 on hit, another source of self speed drops.
Population Bomb can hit 1 to 10 times in a row. Of all things that are probably not callable, I hope this one is.
Ice Spinner is a hit that removes terrain. Pretty interesting.
Glaive Rush causes attacks from the enemy pokemon over the next turn to not miss and do double damage. If this move doesn't finish someone then it is a pretty big risk.
Revival Blessing revives a fainted party member with half HP. I definitely don't think this will be callable but it might be pretty clutch if it targets correctly.
Salt Cure does damage and inflicts salt damage over time to the target, with Steel and Water types taking more damage. Wrapping moves are already pretty devastating so I'm interested in this.
Triple Dive is a water type triple axel/kick.
Mortal Spin is like Rapid Spin's bind removal but with poison instead, which sounds guaranteed.
Doodle changes the ability of the user and ally to match its target. This could get chaotic.
Fillet Away uses your own HP to sharply boost Attack, Special Attack, and Speed. Another risky but strong swing move.
Kowtow Cleave sounds like False Surrender to be honest.
Flower Trick is a sure-hit sure-crit grass move. Pretty neat.
Torch Song is a fire move that boosts SpA. Pretty neat.
Aqua Step is a water move that boosts speed.
Raging Bull sounds like a Tauros thing and its type will be based on which Tauros you use so I doubt it will be callable, but it breaks barriers.
Make It Rain tosses coins and lowers Special Attack, sounding like an Overheat-type move that might be Steel.
Ruination is a Super Fang clone.
Collision Course and Electro Drift are the legendary signatures so I doubt they are callable, but they are pretty strong and get stronger on SE hits.
Shed Tail creates a half HP substitute and is supposed to switch you out, so I wonder how it will work in 2v2.
Snowscape summons a snowstorm.
Chilly Reception creates a snowstorm and switches you out, so here it will just be another snow summoning move.
Tidy Up removes hazards and Substitute and boosts Attack and Speed.
Pounce is a Bug move that lowers speed.
Trailblaze is a Grass move that increases speed.
Chilling Water lowers Attack on hit.
Hyper Drill is a big normal move.
Twin Beam is a 2-hit Psychic move.
Rage Fist apparently has greater power the more times the user has been hit by attacks.
Armor Cannon is a Fire-type Close Combat and Bitter Blade is a Fire-type Leech Life.
Double Shock is a big Electric move that removes electric type from the user and probably requires it.
Gigaton Hammer is a big Steel move that can't be used twice in a row, which probably isn't a problem.
Comeuppance is another counter-type move. Mostly these aren't callable but Metal Burst is.
Aqua Cutter is a simple water +crit move.
Based on descriptions (not the flag), notable removals from Gen 8 include Submission, Vital Throw, Revenge, Grudge, Aromatherapy, Doom Desire, Psycho Boost, Psycho Shift, Autotomize, Dual Chop, Flower Shield, Leaf Tornado, and Power-Up Punch. I for one will miss the rare Magic Coat and Venom Drench triggers as well. Some other removed mons will probably lose their signatures as well but without a description change. Apparently Scald has lost its learners and TM status as well so hopefully we'll get a better picture soon but it's not the end of the world to not know for now.
ITEMS
So far we do not have an item description dump, so this is just based on observations and known reveals and is pretty lacking at the moment.
Ability Shield: Protects you from ability loss. Very niche.
Loaded Dice: Boosts chance of higher multihits. Niche.
Covert Cloak: Acts as Shield Dust and blocks all secondary effects. Actually a pretty solid item as I've mentioned before, and on a Magic Bouncer you become immune to almost all forms of debuffs.
Mirror Herb: Copies enemy stat boosts once. Opportunist is probably a better version of this as a permanent ability and you can get more bang out of your item slot.
Booster Energy: As mentioned, can be used with a Legendary Gimmick Ability to boost your highest stat in some way. Not sure if it's worth it, but it's an option available to everyone.
TERASTALLIZATION
So far we don't really have exact numbers on this, but something new we learned about via previews since the last time I posted was that terastallization supposedly preserves your original STAB type boosts. This means that dual type mons still have some kind of advantage, like if you terastallized Mew and Victini to the same thing then Victini would still have STAB on Fire moves compared to Mew with only Psychic. I think this could be nice offensively to spread out your STAB, like to stack on or with the -ate abilities for more chances of a boosted move. I won't go too much into this as I want to get more exact info on how it interacts with things, but it sounds like it could be more interesting decision making for teambuilding, though only applicable to one mon. I will miss dynamax though and honestly I'm already worried about facing different varieties of bulky ghosts or whatever other horrors that may arise.
Overall I think the biggest lesson I've learned through manual mega strategies is that at some point I forget to mega on turn 1, and I think this will probably happen to me with terastallization. Speaking of megas, I feel like they won't be able to terastallize in the hypothetical future national dex mechanics based on not being able to dynamax, but I don't really know how that's going to go down either.