Ok, now with the end of circuit playoffs, I'll share some of the teams I used during the tournament.
Larvesta Hyper-Offense
https://pokepast.es/e2b26e63f7bc1c89
https://pokepast.es/9e113ff1276594dd
With the existence of Grookey, building traditional hyper-offense is pretty hard, and this is probably the only successful hyper-offense team I have built this generation. There are two versions, because the first version had Onix from shortly before Zigzagoon was banned, and I changed it for Mudbray since it might be better, but I haven't had the chance to experiment enough with it yet.
Anyway, this build is basically just fast strong attackers together, coupled with Larvesta to hard check opposing Grookey and maintaining momentum with its U-Turn. 9 speed on Larvesta allows it to underspeed something like Timburr or other slow Pokemon to be able to send in a frail attacker safely. The team focuses on overloading the opposing steel-type, stacking many Pokemon walled by the steel types to wear them down so that one can sweep. Abra is Life Orb and has both Submission and Fire Punch, to be able to hit both Pawniard and Ferroseed, removing/weakening them for the rest of the team. Onix has Body Press, which 2HKOes Ferroseed. Life Orb Staryu and Scarf Porygon are the other Pokemon that enjoy steel types being removed or weakened. Life Orb Staryu is particularly hard to switch into if the opponent doesn't have a Ferroseed, since even Berry Juice Pawniard gets OHKOed by an Analytic Hydro Pump. Staryu can also act as emergency removal for Larvesta if it really needs rocks gone. Grookey is on the team to protect the team against ground types, Diglett in particular for Staryu. Onix can act as a setup sweeper with Dragon Dance once Ferroseed is worn down. Hyper-offense without hazards is weird, though, so running Mudbray over it could be an alternative to have rocks while still smacking Ferroseed hard with Close Combat.
The team is relatively weak to Trapinch, which can remove Abra, Porygon, and Staryu if weakened. Life Orb Staryu is also a very shaky spinner, so if it can't remove rocks, it might be difficult to deal with Fighting types, and more importantly Grookey, since Larvesta gone means Grookey 1v5s the rest of the team.
Replay:
LC Circuit playoffs Round of 16 vs Prodigezz:
https://replay.pokemonshowdown.com/smogtours-gen8lc-597822
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Carvesta
https://pokepast.es/23e788627636fdd4
This is a team that's been known for some time, I think. This team uses the Larvesta-Natu-Staryu core, which I think is really good, since keeping rocks off the field allows Larvesta to show its true potential.
Carvanha is in my opinion, surprisingly good despite being in a meta with Grookey. Receiving Flip Turn this generation was a huge buff for it, since it allows it to deal damage to the Pokemon it can't KO, and switch out before taking a hit. It threatens to OHKO a good chunk of the metagame, with only a few Pokemon like Ferroseed and Berry Juice Pawniard being able to take more than two hits from it. It acts as a very good wincon against many teams. Shoutout to
wesh papillon , from who I got the idea of using Carvanha myself.
Larvesta is the main support for Carvanha, being, once again, a solid check to Grookey, threatening to burn it with Flame Body, discouraging it from using Grassy Glide, and pivoting out of it with U-Turn. It's also the Fighting type check on this team. It once again has 9 speed, to be able to slow U-Turn, and send out Carvanha or Natu safely on Pokemon such as Koffing and Timburr.
Natu is extremely good in the current metagame, and pairs well with Larvesta by preventing hazards from going up with Magic Bounce. It can almost always switch into Ferroseed and completely shut it down, being able to spam Roost on it and threaten it out with Heat Wave. Against teams that rely on Ferroseed to set rocks, Natu can by itself guarantee they never go up, which helps Larvesta immensely. Natu can also act as a shaky secondary Fighting and Grookey check, if Larvesta is weakened, or if rocks are up. I had Sucker Punch with a weird spread because I wanted to have it as a surprise weapon (which worked out in the second replay), but it can easily be replaced by U-Turn or Calm Mind.
Staryu pairs well with Natu and Larvesta as a Rapid spin user. The set is defensive Staryu, to be able to repeatedly switch into Natu better, with the added bonus of not having to worry about paralysis with Natural Cure. Defensive Staryu can also outstall Pawniard's Knock Off with recover, which greatly helps it to be able to use Rapid Spin safely. This Staryu doesn't hit as hard as offensive versions, but Scald threatens the opposing Pokemon with burns. Ferroseed being often the Staryu switch-in, Scald burning Ferroseed is extremely useful, since it halves the damage Natu takes from Ferroseed's Knock Off, allowing it to prevent rocks from getting up much more safely.
Mienfoo is there as a Pawniard switch-in, and because it's just such a good Pokemon. Taunt provides a lot of utility, such as preventing Koffing from using Pain Split or Mareanie/Foongus from using Recover.
Ferroseed is the last Pokemon on the team, has Stealth Rock, and acts as a Water type switch-in and Porygon check.
I think this team is very solid. It needs to be more careful against Pawniard teams, since it has an easier time setting up rocks against Natu. Nevertheless, I've had good success with it, with this team, and with the Larvesta-Natu-Staryu core in general.
Replays:
LC Circuit playoffs Round of 16 vs Prodigezz:
https://replay.pokemonshowdown.com/smogtours-gen8lc-597821
Another francophone tournament vs Daruma:
https://replay.pokemonshowdown.com/gen8lc-1474658077-6mkf7efzj712n46hicmwnzbtjw6hc5xpw
Here's also a Youtube video of
TheKingKarp using this team on ladder :
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Frillish balance
https://pokepast.es/f72cdc9016326f2c
https://pokepast.es/0c5b7a713db062c3
Here is a pretty balanced team to finish off, that I used in circuit finals. This again has two versions, one with Diglett, and another with Trapinch. I believe the Diglett version is slightly better. The Diglett version has the advantage of also being a hazard stacking team, with Stealth Rock on Diglett, Spikes on Ferroseed, and Frillish as a spinblocker in case there's Rapid Spin Staryu.
I probably won't say too much about this team, since it follows a pretty standard building core. It has Calm Mind Natu as one of the wincons. Frillish is also very good in my opinion, acting as a solid Natu check, and also probably the best check to fire types possible, maybe after Munchlax. Explosion on Ferroseed is very cool, allowing it to net surprise KOs on Natu and Mienfoo after Knock, and Grookey. The rest is pretty standard. The team is slightly weak to Grookey, so preserving Koffing well is ideal, with Natu and Ferro as secondary shaky checks.
Replays :
LC Circuit playoffs Finals vs Toadow:
https://replay.pokemonshowdown.com/gen8lc-1487683565
Another francophone tournament vs Foukrou:
https://replay.pokemonshowdown.com/gen8lc-1480454308-shw8cd6d8jny8oy86rh518t8lalr6b4pw
Alright that was a handful to write. I'll probably dump some more stuff once LCWC is over XD