Incineroar, Rillaboom, and Scarf Urshifu-Rapid-Strike 
is a fantastic Balance pivoting core where each pokemon covers each other's weaknesses. Can put pressure on the majority of the meta and difficult to check. Core also brings a lot of support for the rest of the team, in damage reduction, Fake out, pivoting, and having a fast nuke option that can break down a lot of the meta. The core of Incineroar, Rillaboom, and Scarf Urshifu-Rapid-Strike creates a lot of free turns through this and why you'll usually find Gholdengo 
or Kingambit 
on those teams, very effective set up pokemon that can wreck teams on their own.
I've also seen variants use Amoonguss 
over Rillaboom who brings redirection, healing, and sleep. It is especially strong this format because Incineroar has the ability to knock off opposing safety goggles and consistently force out grass types (apart from Ogerpon-Wellspring 
who Amoonguss can beat anyway). This change makes set up easier, as well as helps with the Raging Bolt 
and Archaludon 
matchup. This is done by protecting Urshifu from their strong electric moves and safely putting them to sleep, retreating to regenerate off the damage. Dragons in general are a threat to the aforementioned core due to how well they can take the hits and slowly break their team with support.
Speaking of Raging Bolt , it has shown time and time again that it's here to stay, having a great matchup into the Incineroar, Rillaboom, Urshifu-Rapid-Strike Balance core, or in other words, the revolving door. Raging Bolt is also a threat to the still ever-present Tornadus Urshifu-Rapid-Strike 
lead, meaning it can fix quite a few holes in teams. I believe its struggling more as Landorus 
rises in popularity with the duo though.
Landorus-I can't be seen as a solid niche pick anymore, because it's now a meta staple! Landorus rose in popularity in Regulation E alongside Gholengo , due to the ability to check it and be it's best offensive partner, putting pressure on the handful of Make It Rain resists teams had. But a big issue it was facing was the dominance of Landorus-T 
. Took up too many spots and Landorus-I had a hard time finding a place in the meta. Now that Incineroar is available, It's the far more dominant Intimidator and not only brings Landorus significantly less competition, but also brings it another target. Both Incineroar and are the best DLC pokemon added, and both get deleted off the field by Landorus . In fact, almost half of the meta is hit super effectively by the Earth Power Sludge Bomb combination.
You may have noticed that the two pokemon above have one bad matchup in common...Chien-Pao 
. Chien-Pao seems to have become a huge sleeper pick as more people gravitate away from it due to the newly added Incineroar . But people really forget how much Chien-Pao can actually hit in this meta, it is the ultimate 1v1 pokemon and a great support option simply by being on the field due to due to sword of ruin. Out of my personal top 20, in a 1v1 situation, beats; Incineroar , Flutter Mane 
, Rillaboom , opposing Chien-Pao (technically), Gholdengo , Tornadus , Ogerpon-Wellspring , Kingambit , Urshifu-Single-Strike 
, Landorus-I , Raging Bolt , Landorus-T , Roaring Moon, 
, Whimsicott 
, Iron Bundle 
. That's 75% of the meta that Chien-Pao: is capable of annihilating. I know this doesn't directly correlate to meta matchup, as a double up or something like intimidate changing the outcome of the matchup, however this is still an insane feat. Chien-Pao by itself is a ridiculous pokemon, and what further boosts it is how well it can pair up with pokemon who appreciate the extra boost. Urshifu-Rapid-Strike, , Rillaboom , Ogerpon-Wellspring , Iron Hearthflame, 
, etc.
A cool pokemon I'd like to mention that has received hate is Gouging Fire 
. Both it's supportive movepool consisting of Breaking Swipe, Howl, Snarl, and even Dragon Tail, as well as Offensive movepool with Dragon Dance, Heat Crash/Flare Blitz, Dragon Claw/Scale Shot, Stomping Tantrum, Stone Miss, Crunch, etc look pretty good. It even has recovery in morning sun if it wants it. Pokemon has ridiculous amount of bulk to pull off the sets, being bulkier than Kingambit and relative bulk to Intimidate Landorus-T for example. What stands out the most though, has to be its signature move. Burning Bulwark has the downside of not protecting you from parting shot or spore (its two best items answer the two, so you'll only have to watch out for one), but burns with contact, like spiky shield. Making Iron Hands 
, Rillaboom , Chien-Pao , Ogerpon-Wellspring , Kingambit , Landorus-T , Roaring Moon , etc second guess before attacking you, as one wrong read can lead to a practically useless pokemon on their side, is incredible. Support sets can stick on the field and neutralise Incineroar switch ins with Howl, or cripple special attackers like Gholdengo and Flutter Mane with Snarl. Dragon Dance sets also pose a threat, being able to 1v1 the majority of the meta and have an even easier time setting up with Fake out and redirection support. It's also a good way to make up for Gouging Fire 's rather underwhelming speed tier, making it outspeed this like Roaring Moon and Adamant Chien-Pao when you invest. Gouging Fire does notably face issues as you'll probably sacrifice your Incineroar slot in the building process, and Clear Amulet sets can be pinned by Fake out spore if you're not careful. I think it's a very cool pokemon and felt I needed to explain what it fulfils further.
A relatively unorthodox pick I've seen on ladder a few times is Rocky Helmet Latias 
. Its typing is poor into Flutter Mane and Chien-Pao , but walls Urshifu-Rapid-Strike , Iron Hands , High Horsepower Rillaboom , and the popular Ogerpon 
formes. Packs damage reduction and a great overall stab in Mist Ball and has the Draco Meteor nuke option. Has Tailwind, Breaking Swipe, Helping Hand, Recover, and Dragon Cheer as solid support moves. Latios 
also looks like it can preform the same set, sacrificing bulk for power. Or even just an all out offensive set, since it wields all the coverage you could possibly ask for and a good speed tier. Though I think the Offensive sets will be much more niche as many pokemon can replicate it.
Pelipper Archaludon 
has been a popular archetype since Day 1, as Archaludon being able to spam an electric type Meteor Beam is absolutely ridiculous, allows for more defensive EV spreads with as little as Special Attack as 36 Modest. As most of these teams run Urshifu-Rapid-Strike , Self Surging Strikes or Self U-turn is effective for stamina boosts, making Archaludon wall the majority of the meta. It can also run Stalwart on some niche teams, ignoring Amoonguss or Ogerpon-Wellspring from stopping what it can do best. Not to mention Archaludon has a superb defensive typing and when paired with Incineroar and Amoonguss it can really stick on the field, setting up to one shot your entire team. Its poor Special Defense unfortunately locks it into Assault Vest as an item to not be annihilated by Flutter Mane , but not many want to go for Fake out and give you a stamina boost. I don't expect this archetype to ever be bad this Regulation however I do expect it to fall off a bit after new toy syndrome dies down.
Porygon2 
and Farigiraf 
Trick Room is seeing success right now, Incineroar being a fantastic enabler that can also parting shot into your sweepers to not waste valuable TR turns. I've seen the standard Ursalunas 
, 
, Kingambit , and Torkoal 
. But something that piques my interest is Araquanid 
. One of the slowest pokemon available and with water bubble, can 2hko even resists. Only a handful of pokemon live a Tera Water Wave Crash and even those may have a bad matchup into Araquanid , such as Amoonguss who falls victim to Substitute. I think these teams are doing pretty well right now, especially because they function as Semi-Room compositions and have a strong Balance mode.
Lastly, I'd like to cover Indeedee 
Psyspam, which is much better right now. The trick room variants now have access to Hatterene 
, who is harder to stop, as you can't call your matchup fine because of a dark type anymore. Even Incineroar who can stomach 3 or so hits struggles to do much due to Hatterene 's Magic Bounce. The duo does now begin to find issues into Gholdengo if Hatterene doesn't run Mystical Fire. That's not all though! With the Indigo Disk, Armarouge 
has gained access to Meteor Beam and now Incineroar isn't a reliable answer but set up fodder for Armarouge . Life Orb was bad? Now imagine facing it at +1, wow. Indeedee has become even more versatile now that Expanding Force also spread to fast threats outside of Trick room. Iron Crown 
has been terrorising the ladder, giving Psyspam a new light. However, I don't think these Iron Crown teams are very good, in fact, I consider Iron Valiant 
the better Expanding Force user right now. This is because of how versatile it can be when you look at its supportive movepool, and having a more consistent option of hitting Incineroar and Kingambit (ohkoing with Helping Hand). The two are some of the most popular pokemon and Iron Crown not bring able to damage them or relying on Focus Blast is a bad look. Iron Crown is also fundamentally not a reliable pokemon, the two pokemon it wants to snipe with Tacheon Cutter just outspeed and ohko it, and it struggles to play into a lot of the top pokemon right now (the previously mentioned Incineroar and Kingambit , Gholdengo , Ogerpon-Hearthflame , Landorus-I, Roaring Moon , etc). While Iron Valiant 's extra speed and superior offensive typing let it best the majority of said picks. Not to say Valiant is without issues either, it's bulk is very underwhelming and struggles to damage Gholdengo or Rillaboom , and this is one of the only teams it can actually work so I can see it as a niche pick.
To end it off, here's my personal top 30 pokemon right now
1. Incineroar
2. Flutter Mane
3. Amoonguss
4. Iron Hands
5. Urshifu-Rapid-Strike
6. Rillaboom
7. Chien-Pao
8. Gholdengo
9. Tornadus
10. Ogerpon-Wellspring
11. Kingambit
12. Landorus-I
13. Urshifu
14. Raging Bolt
15. Ogerpon-Hearthflame
16. Roaring Moon
17. Landorus-T
18. Whimsicott
19. Iron Bundle
20. Farigiraf
21. Porygon2
22. Archaludon
23. Dondozo 
24. Dragonite 
25. Regidrago 
26. Tatsugiri 
27. Glimmora 
28. Pelipper
29. Indeedee
30. Walking Wake 
