I did not expect a Pokemon Home release date to drop while I was asleep, nor did I expect it to drop so soon - so I guess I'll throw my hat into the ring on this. I'll make my opinions straightforward here - Unban, Unban Cautiously, Ban, Abstain.
Annihilape - (Unban Cautiously)
With the influx of new threats, higher power level, and varying move options, I think the meta could adjust to Annihilape... could being the operative word here. What worries me more is how playstyles are invalidated because of Annihilape and whether or not that would be healthy for the meta, even with the new options and higher power level available. So I'm for letting it roam OU again, but wouldn't be surprised if it was suspected again in the future.
Basculegion - (Abstain)
I think most of us here understand that Last Respects is what will really push Basculegion into Uber territory, so I'll avoid commentary until it's decided what we're all going to do about Last Respects as a move.
Chi-Yu - (Unban Cautiously)
Chi-Yu was one of those Pokemon that just naturally exerts offensive pressure even on supposed checks, it has a fantastic type combination, a wonderful Special Attack stat, and (what pushes it over the edge) a monstrous ability. I think it should be tested just in case the meta has adjusted to it, but I don't see it staying very long.
Chien-Pao - (Unban)
This is one of the few Pokemon I semi-confidently feel will be manageable enough to stay in OU in my opinion. We're getting quite a few threats that I feel will be able to handle Chien-Pao and it'll definitely feel less centralizing than it once did. Time will tell though, Chien-Pao's ability is pretty nasty and does invalidate some serious checks.
Espathra - (Ban)
It's not that Espathra is outright broken or more powerful than a lot of the threats that might be released, it's got an analogous issue to Shaymin-Sky as to why it's frustrating - a lot of it comes down to aggressively frustrating speed and matchup luck. The meta would be actively worse with Espathra in it, and it's one of the few Pokemon on here that I really would not like suspected at all.
Flutter Mane - (Ban)
That STAB combination with those stats, coverage + utility options is still overwhelming - while it can be exploited, especially with the new options coming in, I don't think I can overstate just how deadly STAB Moonblast + STAB Shadow Ball coming off of a base 135 Special Attack stat with 135 base Speed backing it up is (not to mention Tera, Power Gem, Energy Ball, Thunderbolt, and the myriad of other options it can run. A suspect of Flutter Mane feels pointless to me at the moment.
Houndstone (Abstain)
Same thing with Basculegion, I'll avoid commentary until it's decided what we're all going to do about Last Respects as a move.
Iron Bundle - (Ban)
Iron Bundle exerts an unhealthy amount of pressure on the meta simply by virtue of a speed stat that's even higher than Flutter Mane, Quark Drive to allow for even more shenanigans, and Tera further making things unpredictable. While I feel that it could potentially be worth suspecting upon the release of the DLC, Iron Bundle could potentially get even better with the threats returning from Pokemon Home thanks to a lot of synergistic partners and new targets that it can handle. So my vote is staying on ban for now, but I could be wrong.
Landorus (Incarnate) - (Ban)
This Pokemon is, without question, always going to be one of the most broken Pokemon on this list. Its typing, movepool, and stats are insane and it's heavily centralizing - keep it banned.
Magearna - (Unban Cautiously)
I feel that Magearna's presence could potentially be healthy for the meta - Steel/Fairy is an incredible typing, and would help certain threats feel a little more manageable. From what I understand as well (but I'm not 100% on this) Magearna received some movepool nerfs. I'm in favor of letting it roam when Pokemon Home drops, to see if it could feel healthy within the meta.
Palafin - (Unban Cautiously)
While Palafin definitely deserved to be suspected and banned previously, I don't think that it was "obscenely" broken as it was predictable to play around given the right circumstances. With the new Pokemon coming in from Pokemon Home, I feel that Palafin has a chance to be kept in check, and thus should be let out and watched carefully.
Regieleki - (Unban Cautiously)
To be honest, I'm personally not too worried about Regieleki, and I wasn't really worried about it back in Gen 8 either. Sure, it's a great Pokemon, but the only thing that has me worried about it is whether or not Tera will push it over the edge. However, I feel that its Tera-type choices will be very limited compared to many other options on this list. I would simply say "Unban" for it, but the degree of uncertainty that hangs over my head regarding what Tera means for it is what keeps the "cautiously" in my pick.
Spectrier - (Ban)
I thought about it for a while even before the announcement, and while I was initially leaning towards "unban cautiously", I'm ultimately going to say that Spectrier shouldn't be tested. My justification? Look at Calm Mind Hatterene with Draining Kiss. Spectrier also has these options but is much faster with STAB Shadow Ball as well. Sure it may not be bulky and has a harder time switching in, but it truly feels like a problem that the meta just isn't prepared to handle yet. Like with Flutter Mane, maybe it might be worth testing upon the DLC release, but not now.
Urshifu (Single Strike) - (Unban Cautiously)
Conversely to Spectrier, I was initially leaning towards "ban", no question. However, the more I thought about it, the more I realized that Urshifu-Single Strike could potentially be healthy in the current meta. For one, it's the concrete Kingambit switch-in that everyone's been looking for, for two Pokemon such as Iron Valiant, defensive Hatterene and other threats scare it quite a bit, and three, it would sort of act as an "in-between" for Dark offense and justify the inclusion of more fairies to help with the current Dragon-type dominance in OU at the moment. I wouldn't be surprised if it got banned if unleashed, but I still think it's worth a test.
Zacian - (Unban Cautiously)
Since it was mentioned above by a few users, I would be open to seeing Zacian suspected in OU. Its attack was nerfed to 120, and its movepool, while great, is still lacking some serious options and the tier needs more powerful Fairy-types as I mentioned earlier. If it had access to moves like Earthquake, it would likely be a different story, but Zacian suffers from 4MSS in many ways - especially on Swords Dance variants - having to rely on Tera if it wants to make up for this problem. I wouldn't be surprised about a ban, but I think it's worth testing.
Zamazenta / Zamazenta-Crowned (Unban Cautiously)
I was one of the biggest advocates for Zamazenta-Crowned's testing in OU in Gen 8, and I'll continue to vouch for it here - but I'll also vouch for testing regular Zamazenta as well. I feel that Zama-C would be a healthy Knock Off absorber, while Zama-normal would be a potentially fun, strong, albeit predictable Choice Band / Choice Scarf user. Definitely worth a test, but I also wouldn't be surprised if, like Gen 8, it would have the Gen 2 Celebi problem of just being really, really hard to wear down.