Impressions after second Home day, having played way more games today:
-Regieleki Ban definitely improved the meta despite Zapdos and Thundurus-T trying to take it's place.
-Saw less Ursalunas today than yesterday, but the few I saw were just as destructive as always, with or without Trick Room. I still think this Pokemon is the next one that should be banned.
-Most Magearnas I saw today were Trick Room + Eject Pack, which aren't too dangerous. My counterplay to Stored Power sets was the same and it never gave me problems. I finally saw some Specs sets and for now it isn't looking as broken as last Gen, but I do think it will eventually break the Mon, just not yet.
-Chien Pao is extremely strong and I have seen it winning vs teams with 3 Fight Mons + Magearna. Not 100% sure it deserves Ban, but it somehow looks closer to it than Magearna.
-Neither Zamazenta have looked more than "just a solid Mon" to me. They do seem to be an autowin vs the physical based HOs everyone is trying to use these days... but only vs that. The rest team structures look naturally fine vs them. Probably Crowned version would look broken to me if Rest still had 16 PPs, but with just 8 it can't last that much without big support. Regarding Hero one, Iron Valiant looks like a better Mon outside of Chien Pao match-up.
-Just like yesterday (but having played more games) saw exactly one Sneasler and not well used (it was SD + U-Turn), so still can't form an opinion about him outside of theorymoning.
-Once the meta stabilizes and slows down, I am worried about Hoopa-U and Heatran. First has ridiculous power vs slower teams even without Tera, second traps something with Magma Storm, Terastalizes and uses Taunt + Tera Blast to remove answers to non Tera variants. For now it's just Grass Tera, but I am pretty sure people will come up with more ideas. Glad this Mon at least lost Toxic, cause I have been hating his presence since SM
-Sun looks to have completely dissapeared from the ladder and I am not really sure why. Fear of Ursaluna TRs counterteaming? Might be that, but Rain is actually common.
So, to sum it up:
Ban: Ursaluna.
Watch now: Chien Pao and Magearna.
Watch in the (not immediate) future: Heatran and Hoopa-U
Fine: Doggos
Absent and misterious: Sneasler
-Regieleki Ban definitely improved the meta despite Zapdos and Thundurus-T trying to take it's place.
-Saw less Ursalunas today than yesterday, but the few I saw were just as destructive as always, with or without Trick Room. I still think this Pokemon is the next one that should be banned.
-Most Magearnas I saw today were Trick Room + Eject Pack, which aren't too dangerous. My counterplay to Stored Power sets was the same and it never gave me problems. I finally saw some Specs sets and for now it isn't looking as broken as last Gen, but I do think it will eventually break the Mon, just not yet.
-Chien Pao is extremely strong and I have seen it winning vs teams with 3 Fight Mons + Magearna. Not 100% sure it deserves Ban, but it somehow looks closer to it than Magearna.
-Neither Zamazenta have looked more than "just a solid Mon" to me. They do seem to be an autowin vs the physical based HOs everyone is trying to use these days... but only vs that. The rest team structures look naturally fine vs them. Probably Crowned version would look broken to me if Rest still had 16 PPs, but with just 8 it can't last that much without big support. Regarding Hero one, Iron Valiant looks like a better Mon outside of Chien Pao match-up.
-Just like yesterday (but having played more games) saw exactly one Sneasler and not well used (it was SD + U-Turn), so still can't form an opinion about him outside of theorymoning.
-Once the meta stabilizes and slows down, I am worried about Hoopa-U and Heatran. First has ridiculous power vs slower teams even without Tera, second traps something with Magma Storm, Terastalizes and uses Taunt + Tera Blast to remove answers to non Tera variants. For now it's just Grass Tera, but I am pretty sure people will come up with more ideas. Glad this Mon at least lost Toxic, cause I have been hating his presence since SM
-Sun looks to have completely dissapeared from the ladder and I am not really sure why. Fear of Ursaluna TRs counterteaming? Might be that, but Rain is actually common.
So, to sum it up:
Ban: Ursaluna.
Watch now: Chien Pao and Magearna.
Watch in the (not immediate) future: Heatran and Hoopa-U
Fine: Doggos
Absent and misterious: Sneasler
I think explanations on why these 3 are very broken has been done to death now. I don't see a healthy future for these pokemon. Mage can be teched to beat just about anything it seems, forcing Zama-C out is one of the most aggravating and painful tasks ever, and Chien is only here because these 2 manage to successful employ my favourite metagame strategy called broken-check-broken. Would be glad to see em go.
I do think it is broken under trick room, but trick room is definitely A: enabled by broken ass Mag and B: preying on nonsensical day 1 lazy offence teams. Even if trick room should adapt to losing the Gears that make it turn, I think it will still be more on the gimmick end of things. Outside of trick room Luna is still definitely a monster, akin to kingambit in the previous meta. All the same I think it could and should be deserving of time in the tier without the big 3 mentioned above. Luna so far seems like it heavily preys on the extreme ends of the playstyles, Hyper offence and stall, and imo having limitations placed upon those playstyles can be healthy. Going forward should Luna further restrict the building of all other playstyles as well though, I could definitely find myself supporting its ban.
On the fence about this, ID sets on it dont hit nearly the same as his Father's do, as lacking steel typing really sucks. Being faster is cool and all but the only speed tier this one is taking over Crowned is Chien-Pao, which ideally is banned regardless so I don't think this benefit matters much. It is also weak as piss, but it is a good tera abuser and it having more set options definitely sets it apart, but no individual set has felt any bit as impressive as I would hope. Also feels hard to actively fit on teams. I think this too, just like Luna, might be preying on lazy early offences, but this prediction I could also see being wrong in the future, and if so, would support a suspect/ban. 
I think this mon will fall off overtime, not just because haha run covert cloak but because I do not think Poison is as spammable of a stab as you'd hope, so forcing something out with it safely while being able to click dire claw isn't often a free situation, and more often than not a hard read (which has a 50% chance to amount to nothing, and a 50% chance to be annoying) and spending games into BO/Balance fishing for poisons or sleeps and wittling down whatever tusk or lando or chomp you load into just seems like a hunk of shit. And then yeah, ofc, there is still covert cloak poisons to be looked into the future, but this point I do not think matters much with the mon options we have at hand. 
genuinely don't know what to say on this one. Many seem to think it will be a future broken and I can definitely see it. Has been getting high value in current meta as well, but does seem to have some level of 4mss, for whatever that is worth. 
it is definitely a FRAUD . . .
- uninvested Ice Fang is a 4hko on defensive landorus 96% of the time, all while lando can bounce in and out if it so desires and has actual (minor) healing with leftovers. If you're not running ice fang, good luck. EQ does about 35 from lando at +2 on zama, which isn't damage you can really be affording to take. Helmet Lando also chips it even further since every move in Zama's arsenal is contact.
- Ice Fang 4HKOs, no other move comes close. Zap also has reliable recovery and its it on the special side, completely subverting any boosts it may have accumulated. Zama pretty much can't beat Zapdos regardless of what it runs, and every hit it tries runs the risk of static screwing it over completely.
- needs Crunch for a 3hko and if you don't have it you're unable to do much of anything to it while it gets to click glowking buttons on you with little fear. If you do have crunch, it can pivot out and heal back up, and it means you're probably missing something else.
- this one's a bit complicated. Bulky tusk is a pretty solid check, especially if Zama's expended Dauntless Shield and swapped out, although it doesn't do a whole lot of damage in return. Offensive can hit it really hard on setup turns but is capable of being KO'd back by body press after multiple boosts. It's a decent soft check if nothing else but shouldn't be your only option. If you are tera fairy on zama you can set up on tusk much more easily, but making fairy your tera type makes you lose to several other things.
- if you're not running behemoth bash you can't touch valiant for any meaningful damage without several turns of boosting, and behemoth bash is generally the least useful move that you still might need. Valiant also does a lot back on the special side and can force zama out a few times, even though it, like zama, has no recovery, making it strictly an offensive check. You can Tera Steel to shore up the moonblast issue, but then you have a much harder time vs other grounds in the tier.
- Ice Fang is a 3hko and forces dragonite to roost, but if you're not running Ice Fang you can only 3hko it with a +6 body press, all while dnite has opportunities to boost alongside you.
- +3 body press is a 2hko 75% of the time, but if you've already expended your dauntless shield you're gonna need multiple turns to boost. none of zama's other coverage moves do anything of note, and each hit runs the risk of proccing flame body and ruining you on the spot. Fiery Dance is a 3hko at worst even unboosted, and you will be giving volc free turns in any situation but the absolute best for you.
- you should always be running crunch imo but including this here just because you hard lose to him if you don't have it. He even has reliable recovery!
- sure you get psychic fangs and/or wild charge but have you seen how many different moves I've already listed? Neither of those are terribly worth it on IronPress crowned, especially wild charge. Haze means zama pretty much does nothing unless you're running like, the 6th best move for this one mon.
- 1v1s you unless you have behemoth bash, although if you're tera steel it'll take a really long time for it to do that.
- see above.
- behemoth bash and psychic fangs both can 3hko, but you will be taking helmet chip or risking a spore to do it. You can run Substitute to get around Spore, but then you're probably missing Behemoth Bash or Psychic Fangs and you two will kind of just enter a stalemate. If Zama's already tera'd into not steel for whatever reason you can also get clear smogged, which is irritating.
- did you forget we had 3 unaware mons? unaware also ignores the defense boosts from zama so body press is always a clean 3hko. There's nothing Zama can do here, even wild charge is a 5hko and not a good move to run overall.
- Crunch 3hkos spd dirge but teraing your dirge fixes that, and since it has unaware it doesn't care about body press even if it's not immune to it. Torch Song also ruins zama - it even bypasses substitute!
- this guy's such a sleeper pick right now. substitute and ice fang can ease this matchup, although if clodsire goes tera water there's not much you can do. Clod can theoretically also slot yawn over toxic, which bypasses substitute and forces zama to switch out repeatedly.
- takes negligible damage from anything barring behemoth bash (but also doesn't do a whole lot back, so don't rely on this)
