These three are pretty obvious quickban candidates, and based off my experience in National Dex they'll just do the near same exact thing they did to get banned there.
- Magearna is way to versatile and is hard to prep for in the builder and can be a real struggle to scout sometimes unless you want one of your Pokemon to be crippled / taken advantage by it. Not to mention how Tera just turns it into an absolute menace with either Tera Fairy with Choice Specs sets, or Tera Water / Grass / Flying / whatever else on defensive sets and some offensive sets as well.
- Regieleki was a Pokemon that was not very good as it could not hit Ground-types. It now has Tera Blast, which lets it hit Ground-types. It's speed tier is very large as well, meaning that a majority of Choice Scarfers bar Iron Valiant and Roaring Moon can actually threaten it. It also can just Volt Switch on fat specially defensive blobs that would like to sit on it. Don't really think I have to explain how this Pokemon will be banned, if Ting-Lu and Gastrodon are reliable "checks" to it I don't know what to say.
- Zamazenta-Crowned may have been nerfed a bit but Body Press totally makes up for it. It's insanely hard to revenge kill and because of Tera it can bullshit through its checks with ease bar like Toxapex, but you can just pair it with Future Sight and call it a day. Howl sets could be used but Zamazenta-Hero does it better because of its faster speed tier.
Chien-Pao now has a very sturdy check in Magearna and is annoyed a bit by Zamazenta returning for the moment, but I still think it's quite nuts. It's common knowledge that it's a pretty damn annoying Tera abuser and can be a threatening Swords Dancer but can be a bit strapped on slots if it wants to be one, but to be honest, I really feel like not much has changed to fully justify this Pokemon being in the tier, and it will really be very little once Magearna and Zamazenta-Crowned depart. There are only a few new Pokemon that can deal with Chien-Pao and the only true one is Magearna, but I don't like having to slot Magearna on every team to have a chance to have a standing chance against it. This Pokemon will just Tera Dark and Crunch through a lot of team at the moment and will often be paired with Heatran to deal with the aforementioned Magearna, so yeah. It's not quick-ban worthy to my eyes as there is some semi-reliable counterplay to it, but it should definitely be looked at down the line.
Heatran is Heatran, and it's good to be Heatran when Volcarona and Magearna are running rampant. Has a lot of good utility in Stealth Rock, Will-O-Wisp, Taunt, and is just really good against defensive teams. Tera Grass / Bug allows Heatran to circumvent the problems it would have like being chipped down by Toxapex with Surf or turning the Ground-type weakness Heatran despises into a resistance against foes like Great Tusk, Clodsire, and Landorus-T. It's a very nice addition to the metagame just like to any it has graced, so it'll be pretty good and will just do Heatran things.
Great Tusk without a Dark-resistance and Rapid Spin, but Spikes immunity and can pivot. I think that Landorus-T has it's uses defensively over Great Tusk, a Spikes immunity is huge in a hazard stack metagame and pivoting is as good as ever. It also has some utility that Great Tusk cannot often slot or doesn't have like Taunt and the hinted at and aforementioned U-turn, and can pivot into Pokemon like Roaring Moon a bit more safely because of Intimidate. They may both overlap a bit but it's not entirely outclassed. I think a set like Earthquake / Stealth Rock / U-turn / Grass Knot can be good, with Grass Knot here for opposing Great Tusk and potentially punish fat Water-types coming into you. Swords Dance sets will be quite nice as well, Tera Flying Tera Blast is quite obvious but I think something like Tera Blast Ice to smash opposing Landorus-T and Zapdos or just standard EdgeQuake sets can work too. Choice Scarf will be good role compression, and the fabled Nasty Plot sets sound really good because I don't see much that can deal with specially offensive Ground-types. Overall it will be pretty good, and while there may be competition with Great Tusk, there's still a bit that differentiates Landorus-T from it.
This Zamazenta unlike its Crowned form will stay in the tier, and I think its a solid addition as speed control and a nice wallbreaker, especially when paired with Future Sight. Choice Band sets with Tera Fighting is an absolute nuke and can even 2HKO resists like Clodsire, Tornadus-T, and Zapdos while also having coverage for Toxapex, Gholdengo, and Landorus-T with Wild Charge, Crunch, and Ice Fang respectively. Howl sets can be okay but I don't know why I wouldn't use another Fighting-type set up sweeper like Iron Valiant or Urshifu-R. Body Press sets with this are not good as for as long as Zamazenta-Crowned is in the tier even with the higher speed tier, giving up the bulk and typing for Leftovers may not be that good. Solid Pokemon overall though, turns out all box legendaries aren't broken!
It got Punching Glove and Swords Dance, and Tera Water as well. It's a really annoying Swords Dancer and can clap a lot of fat builds just with the click of a button. Checks like Toxapex and Dondozo can be exploited by Tera Electric with Thunder Punch and Dragonite you can just click Ice Punch on, or Aqua Jet to avoid being revenge killed with your somewhat mediocre speed tier. Pivot sets with Taunt can be annoying, you can just Taunt, click a button, U-turn out on a check, rinse and repeat. Will be quite solid.
Already said this before but this Pokemon in a metagame without Pursuit is quite nuts, you just click with Choice Band or Specs, or if you want to destroy stall / fat you can Nasty Plot up and it'll be over for your opponent. I have high hopes for this, hopefully will not be a slow attacker that can be easily exploited like it has been in the past.
Very weird Pokemon to see here, but I think it can have a funny niche with Tera Poison / Fairy and Calm Mind + Stored Power. Cresselia itself is quite an annoying Pokemon to take down, and now that it can Tera into a type that can help it deal with Dark-types like Kingambit, makes it even more of a hassle to deal with. It's some tech that is stolen from National Dex but I think it can do pretty good here with a set like Calm Mind / Stored Power / Moonblast / Moonlight and with a Covert Cloak to exploit Garganacl and just turn it into free Calm Minds for yourself. Very funny wincon, may work here but maybe not, I think it'll be okay though.
That sums up my thoughts on some Pokemon coming back here, wanted to post before this thread gets turned into absolute slop.
Go play National Dex if you haven't by the way, very fun tier!