Hey i have a question? Why are broken ass things sub uber/ psuedo pokemon in ou? The ultrabeast are broken AF (Cough cough Celesteela) Zygarde has a sub that cant be broken, Dont even get me started with a weakness policy item. That thing is ridiculous and is VERY easy to bait into.
I'd like to add on David's post, and that is Ultra Beasts that are broken (Naganadel and Pheromosa) are already banned from OU. Aside from Celesteela and Kartana, other examples of viable Ultra Beasts are Blacephalon and Buzzwole. These Pokemon aren't broken, although they are quite annoying in some cases and should be prepared for. However, they are not without their checks, and none of them have yet to prove themselves to be worthy of being suspected.
(I calculate the damage by using the onsite set, however, I use the Specially Defensive spread for special threats and use the Physically defensive spread for physical threats)
Even if Celesteela has amazing 97/103/101 bulk, it's actually fairly easy to keep it in check. Celesteela is mainly used as a Fairy- and Psychic-type resist. Therefore, super effective moves or just powerful moves can actually threaten Celesteela. Fire-types like Heatran, Mega Charizard X and Y, Volcarona all take advantage of Celesteela to either set up or just throw off a powerful attack. Zapdos and Tapu Koko threaten it with a powerful Electric-type move, and the former is able to PP stall Leech Seed and heal off damage with Roost. Powerful attackers include stuff like Ash-Greninja (Transformed: 2HKO with Hydro Pump, 3HKO with Dark Pulse; Still regular: 3HKO with Hydro Pump, 4HKO with Dark Pulse), Mega Mawile (2HKO with Thunder Punch, 4HKO with Knock Off, and 2HKO with +2 Play Rough), Magnezone traps it and eliminates it with Specs Thunderbolt/Gigavolt Havoc, Mega Medicham (2HKO with Jolly HJK), and so on. It's also really susceptible to Knock Off, which gets rid of its Leftovers, and Leech Seed is rather RNG-based, since it can miss (unfortunately) and it's blocked by Grass-types like Tangrowth or Ferrothorn.
Kartana is actually a reason why I think Zapdos/Buzzwole are necessary on a stall team, being able to threaten all the Unaware users and easily getting a sweep. It's also a reason why Buzzwole and Mega Aggron (despite Mega Mawile being the Pokemon it checks, Aggron can actually take several Sacred Sword) is seen in stall teams. It's easily kept in check by powerful special moves, most notably Water Shuriken (assuming Greninja has tranformed into Ash-Greninja, which revenge kills Kartana if it's under 77.3%. Others include Tapu Koko's Thunderbolt, Ice Beam from Magearna, and basically any neutral or super effective (or even not very effective in Water Shuriken's case) can knock it out. Defensively, it can be played around with Heatran, Zapdos, Tangrowth, Torn-t, Celesteela, Mega Scizor, etc.
Blacephalon may seem amazing on paper, but actually it's kept in check notably by these 3 Pokemon: Greninja, Tyranitar, and Heatran. Of course, Chansey, Toxapex, and Kommo-o are also effective checks, but they're not as common as the first 3 checks. Heatran's natural bulk allows it to take any hit that's not Never-Ending Nightmare and KO Blacephalon with Earth Power while Greninja and Tyranitar both resist it's STAB moves and force it out with their powerful STAB moves. Chansey can take Shadow Ball and Never-Ending nightmare with ease, but it's used as setup fodder for SubCM Speed-boosting Blacephalon; Toxapex is quite a good check, since it can break Substitutes with Scald and Haze away Calm Mind boosts; Kommo-o is immune to Shadow Ball because of its ability Bulletproof (Never-Ending Nightmare can hit it tho), and resists Flamethrower. It can also phaze Blacephalon with Dragon Tail.
Buzzwole may seem terrible, having abysmal SpDef and low speed, but it's actually a great physical wall to several of the tier's most prominent physical attackers in Kartana, Zygarde, and Tapu Bulu. It's also able to check Crawdaunt, Mega Heracross, Mega Lopunny, and Mega Gyarados to a certain extent, which are all common threats to Balance/Stall. It's actually pretty threatening if not prepared for, since its movepool includes moves like Ice Punch, Leech Life, Drain Punch, Toxic, Earthquake and even Poison Jab.
If the Ultra Beasts are truly broken af, I think we would have had an suspect test for them a long time ago. But since the ones in the tier are actually still pretty much kept in check most of the time, they aren't really broken. Besides, I don't think Pokemon having the status of "Ultra Beasts" or "Psuedo Pokemon" really matters with what tier they belong to.
