Overall thoughts: This team isn't bad, but there are many Pokemon that are using sub-optimal strategies and movesets. The team composition itself isn't bad, but most movesets need some amount of tweaking in order to adjust to the current metagame. I'm going to fit this team as much to the "bulky offense" playstyle as possible (since you mentioned it in previous posts).
Hippowdon: Immediately, Hippowdon presents some issues. As a Ground type, it faces lots of competition from the likes of the Ground-Flyings, Landorus-T and Gliscor, as well as Clodsire for a Ground-type with recovery and both of Clod and Ting-Lu for a hazard-setting bulky Ground. However, it isn't entirely unusable; you just need to have a really good bulky switchins to cover for Ogerpon-Water, Weavile, and other offensive mons that pose a threat.
As for the moves, Fire Fang is entirely useless. The purpose of a defensive Pokemon is to sit on the field and exert some sort of passive damage or pressure. Hippowdown achieves both with Sand Stream and Earthquake (although Earthquake presents an issue that I will talk about later). Instead of Fire Fang, I recommend Whirlwind. A strong offensive sweeper like Dragonite can really pose a threat against your team, and the ability to phase it out with Whirlwind is really useful. Because your team is generally slow and lacks priority, Whirlwind is a valuable tool to negate these setup sweepers.
Hippowdon @ Rocky Helmet
Ability: Sand Stream
Tera Type: Water / Dragon
EVs: 252 HP / 4 Atk / 252 Def
Impish Nature
- Slack Off
- Whirlwind
- Earthquake
- Stealth Rock
For the EVs, it is generally recommended to use Hippowdon solely as a physical wall instead of a mixed wall. Because Hippowdon doesn't get a 1.5x SpDef boost in Sand like TTar, it's best defensive role is as a physical wall. Leftovers is not a bad item, but something like Rocky Helmet can punish numerous physical attackers such as the aforementioned Dragonite as well as Zamazenta and Roaring Moon. As for Tera, your team is actually decently well off against the Grass STABs of the tier, leading me to think Tera Water is a better option. This also negates a lot of your weaknesses; as a Ground-type, Hippo is susceptable to Kyurem, Primarina, and Weavile, and Tera Water helps with all of these threats, especially physical Kyurem and Weavile. However, if you choose to use Hippowdon as a Ogerpon-Wellspring counter, Tera Dragon is the better option. You do have to be careful about Play Rough variants. Ogerpon usually runs one of Superpower and Play Rough, and Tera Dragon gets destroyed by Play Rough, so be careful about using it prematurely.
Rillaboom: Already, team synergy is getting a bit wonky. Rillaboom is best known for priority Grassy Glides courtesy to its hidden ability, Grassy Surge. I do understand why you opted to use Overgrow over Grassy Surge, as Grassy Terrain negates Hippowdon's Earthquake damage. Because you hope to build your team around Hippowdon, a better offensive Grass type is Ogerpon-Cornerstone. Other than OgerCorner's innate offensive pressure, its Sturdy ability allows it to become a great emergency revenge killer with the help of a good hazard remover. OgerCorner also immediately threatens physically defensive Moltres, a Pokemon that can be problematic for non-TTar Sand teams due to, well, non-TTar.
However, Ogerpon-Wellspring is also a great Pokemon as it can stuff many Waters thanks to Water Absorb as well as nailing Ground-Flyings. You also have Garganacl as a decently solid Moltres check along with being a Rock-type. Since both run very similar sets, I will give the moveset for Ogerpon-Wellspring if you insist on keeping Garganacl, but you can easily replace it with Ogerpon-Cornerstone (I will give more information on how to decide late.)
Ogerpon-Wellspring (F) @ Wellspring Mask
Ability: Water Absorb
Tera Type: Water
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Ivy Cudgel
- Power Whip
- Play Rough
Play Rough is chosen over Superpower due to Pokemon like Kyurem and Dragonite that can easily Dragon Dance (or fire off Specs Ice Beams), and you don't seem to have excellent Pokemon to deal with them (you can't rely on Hippowdon all the time.) This exact moveset can be used for Ogerpon-Cornerstone.
Toxtricity: Toxtricity has the issue of not having good enough coverage. Yes, Electric is a potent offensive type, but Boomburst doesn't give any useful coverage and Poison is walled by almost everything defensive. Case in point, every decently specially defensive Ground type (SpDef invest Gliscor, Ting-Lu, Clodsire) can take little to no damage from even a boosted Toxtricity, and its Brave nature doesn't help at all (+Attack and -Speed, actually tho why Brave?) The ability should also be Punk Rock; it boosts sound-type moves (sound is a sub-category that contains moves like Hyper Voice and Bug Buzz) and gives Overdrive and Boomburst its astronomical power...in the lower tiers. However, the power of OU renders Toxtricity near unviable.
As for a powerful special attacker, I recommend Raging Bolt. Either Ogerpon form from before has base 120 speed, which is respectable enough to deal with many threats. Raging Bolt can help break through slower and bulkier mons as well as offering priority with Thunderclap.
Raging Bolt @ Booster Energy / Leftovers
Ability: Protosynthesis
Tera Type: Fairy
EVs: 4 HP / 252 SpA / 252 Spe
Modest Nature
IVs: 20 Atk
- Calm Mind
- Thunderclap
- Dragon Pulse / Draco Meteor
- Thunderbolt
Tera Fairy helps against faster Dragons; however, you should not use Tera Fairy early game if you have other options to deal with these Dragons. Calm Mind allows Raging Bolt to become a potent midgame threat; it may not fully sweep, but Thunderclap in conjunction with Sand chip can allow Swords Dance Ogerpon to clean up late game.
The choice between Dragon Pulse and Draco Meteor is dependent on which Ogerpon form you choose. Draco Meteor is better with Ogerpon-Cornerstone, as it can seriously dent many Ground types that Ogerpon-Cornerstone may struggle to damage, like Landorus and Gliscor. Dragon Pulse is a more reliable option that allows Bolt to function more late-game, and if you use Ogerpon-Wellspring, Wellspring's coverage against more Pokemon means Bolt does not need to use Draco to support it sweep; instead, it can opt for the reliability of Dragon Pulse.
Garganacl: I did mention Garganacl previously when choosing an Ogerpon form. First, I will critique the moveset. If you want to have a setup Garganacl, you are better off with Iron Defense Body Press, or as most forums say, IDBP. Salt Cure is basically entirely superior to Stone Edge due to Garganacl's lack of immediate damage. With Salt Cure, Garganacl can at least neutralize many setup sweepers that are Water or Steel type, notable Iron Crown, which can easily threaten Hippowdown without many boosts.
From here, there are two directions you can take. If you stay with Garganacl, you can opt for a bulky setup Pokemon that can act as a useful late game win condition if Ogerpon has been damaged. This would also mean that you use Ogerpon-Wellspring, and your team would be more offensive in nature. However, a different option is to use a more general defensive Pokemon that has other means of exerting damage. In my opinion, Sinistcha is a decent fit for this role. Because of Heatproof, its only weaknesses are Flying, Ghost, and Dark, and there are few Pokemon that actually threaten Sinistcha. Its access to Strength Sap also allows it to maintain longevity throughout the game, something it requires as it takes chip from Sandstorm.
First, the Garganacl set. Remember, with Garganacl, you should use Ogerpon-Wellspring and Dragon Pulse Raging Bolt.
Garganacl @ Leftovers
Ability: Purifying Salt
EVs: 252 HP / 52 Def / 204 SpD
Tera Type: Water / Fairy
Careful Nature
- Curse / Iron Defense
- Salt Cure
- Recover
- Earthquake / Body Press
This EV spread, courtesy of Smogon, allows Garganacl to live Power Whip from Ogerpon and Earthquake from Protoboosted Roaring Moon. I have included Curse and Earthquake as a more offensive pressure, trading one defense boost from Iron Defense to one attack boost. This is because Hippowdon easily wear down many physical attackers throughout the course of the game, thus meaning that Garganacl does not require as many defense boosts. However, Iron Defense Body Press is still an option, as explained earlier. Tera Water and Fairy both provide various defensive purposes; importantly, both remove the crippling Ground weakness that many Dragon Dancers rely on. Tera Fairy is generally better against Pokemon like Raging Bolt and Ogerpon-Wellspring, and Tera Water is better against Darkrai (because of Sludge Bomb) and Gholdengo. Both are viable options, and just like IDBP or Curse EQ, you have to make the decision as you test and refine the team.
Now onto the Sinistcha, which will be paired with Ogerpon-Cornerstone and Draco Meteor Raging Bolt.
Sinistcha @ Heavy-Duty Boots
Ability: Heatproof
EVs: 252 HP / 160 Def / 96 Spe
Tera Type: Fairy
Bold Nature
- Matcha Gotcha
- Hex
- Strength Sap
- Stun Spore / Foul Play
One issue of many bulky teams is their inability to slow down fast threats, whether that be setup sweepers or the absurdly fast ChatGPT clone known as Iron Valiant. The EV spread, again from Smogon, outspeeds Adamant Kingambit and Ursaluna. Matcha Gotcha and Strangth sap are self explanatory, and Stun Spore along with Hex allows for consistent speed control along with a 130 Base Power Ghost STAB. However, sometimes offensive threats have set up to the point where even a Stun Spore can't neuter it (or its behind a Substitute in the case of Sub DD Kyurem.) In this case, Foul Play is the better move to guarantee consistent damage and ensure something like Sand chip or Thunderclap from Raging Bolt can finish it off. Tera Fairy removes all of Sinistcha's weaknesses, and Fairy's main weakness of Steel is decently covered by Raging Bolt, notably stuffing Gholdengo and Kingambit as long as its health is preserved.
Tinkaton: Even though a 160 Base Power Gigaton Hammer may be enticing to use, Tinkaton's abysmal Attack just doesn't make it good in OU. Steel is also not a very good offensive type, and you would much rather use something like Gholdengo if you simply want Steel-type damage (Gholdengo is, in my opinion, not the best fit on this team, but this is just an example.) For this slot, I want to lean back more to the Bulky Offense playstyle by adding Galarian Slowking. Glowking has a lot of strengths; notably, it provides a pivoting move to this team. Up until now, no Pokemon can ease prediction by using a pivoting move, and that is especially detrimental to the team's defensive core. Galarian Slowking can use Chilly Reception, which not only makes it a pressuring pivot thanks to Future Sight, it can also reset any opposing weather (not that its that common nowadays.)
Slowking-Galar @ Heavy-Duty Boots
Ability: Regenerator
EVs: 252 HP / 4 Def / 252 SpD
IVs: 0 Spe
Tera Type: Dark
Sassy Nature
- Future Sight
- Chilly Reception
- Sludge Bomb
- Flamethrower / Thunder Wave / Toxic
