Here's my thoughts on everyone in the VR at the moment.
Xerneas is still the best mon in the meta. Even boring sets like Boots Pixi with Spin/Sap/Boom/Volt are threatening and that's without getting into coverage or Metronome. There are few reasons not to have Xern on your squad so this stays at the top.
Eternatus is a weird mon. It can do so many things offensively but also struggle at times to really break through. It can be so tanky at times and also die before you know it. And then it clicks Final Gambit. Etern weighs pretty heavy on the teambuilder though so I think it should stay put.
Imposter hasn't been impressive to me lately. Every time I use it, it feels like a wasted slot. Sure it is useful and annoying to deal with at times and can't be ignored in teambuilding but it doesn't feel near as good as it was last generation. Maybe this is because more offensive mons, like the Dragons, hit themselves super effectively but I wouldn't mind seeing Imposter drop just a little.
Zamazenta-Crowned is another must have. It is pretty hard to build without this mon, and although I've made some successful teams without it before I always miss not having it. Its Speed is honestly so good to have and can help in matchups where you are otherwise really slow using base 90 to 110 mons. I don't think it is quite as good as Xern but it is pretty dang close, especially with sets like Tough Claws rising. I've never been a fan of S+/- rankings though so not sure if it should move.
Giratina is so weird. There's a ladder hero using a set nicknamed *dies* and it is so funny to me cause it feels so true. It is very useful as a bulky Ghost-type but there are also so many downsides to using it at times. Xern, Etern, Kyu-B, Palkia, Dialga, Lunala, Imposter, and more all give it loads of issues but it can also be very useful against mons like Regigigas, Don, Ho-Oh, and other slow passive mons that just can't dent it. But half of the mons mentioned first can all be messed with in return if Tina runs +Spe so that is weird too.
Regigigas is peaking right now. Poison Heal sets are on almost every good team and it can very effectively run three attack sets and is one of the best Spikes setters available. Magic Bounce Ghost-types like Giratina are rare but can check Spikes versions, however they are threatened by Dragon Tail and Wicked Blow variants that are trying to counter FC Lunala. I think a rise could be in order here.
Groudon is another weird mon. Band Adapt sets are still great at punching holes in teams and Mold Breaker Spikes is ok to me but nothing special. Other sets have been seeing use like Magic Bounce, Soundproof, and Prankster but I don't love either of these although they are decent. I think Don has enough variety to stay A- but doesn't need to rise.
Ho-Oh can be a menace. People are finally straying away from passive Magic Bounce trapping sets and exploring Magic Guard offensive utility and offensive Aerilate sets that make Ho-Oh much more threatening. I've seen a Drum Extreme Speed Ho-Oh on ladder that gives me nightmares.
Palkia still hates Tapu Fini a lot (and Ferrothorn at times) but it has a field day on teams that have neither. Para support or even using Rapid Spin helps against Zama-C and Eternatus. I've been seeing some wack Life Orb Shift Gear Palkia lately and I really don't understand those sets but the tried and true mixed Adaptability set is still very good.
Tapu Fini is a great PH utility mon that can also serve decently at other roles like Prankster and Magic Bounce. PH utility with hazards, status, pivot, etc are fine and all but PH Quiver Dance with Scald and Moonblast is a surprisingly effective late game wincon.
Kyurem-Black used Glacial Lance! (Opposing mon lost 100% of its health!) Kyu-B is the embodiment of 0 to 100 real quick. Glacial Lance keeps this mon relevant as it does ridiculous amounts of damage to the meta at +1. Kyu-B also hates Tapu Fini and makes improofing a nightmare if you run coverage for it.
Dialga is yet another weird mon. Opposing Dialga are very annoying to some of my teams and I always feel like I'm wasting a slot when I run Dialga. Its typing gives it so much potential to be annoying to mons like Xern and Etern and the fat Dragons but running sets like FurScales limits its firepower and running full offense on it means you just die to Xern and Etern. RegenVest continues to be a go-to set for this mon but feels like a copout as other sets like Adapt or something are so much cooler.
Kartana is a mon I don't normally build with. The last two times I've used it were RegenVest (don't ask) and Fur Coat (again, don't ask). Kart is cool though cause Sunsteel Strike still does a lot to many things in the meta and although it really hates Zama-C, Drum Triage or a prediction on Choice Band sets can break it as Zama-C is rarely seen with Fur Coat these days. Being faster than Xern, Palkia, and nicher picks like Blacephalon is very nice for Kartana too.
Kyogre doesn't get talked about much. It mainly runs RegenVest and PH utility, both of which it pulls off pretty well but it really can't do offensive sets that I know of outside of rain maybe? A strong STAB Scald is very nice to have though. This mon won't sweep you off your feet but I think it is fine where it is.
Lunala is really good and there is proof of this with people running Wicked Blow PH Gigas and Knock Off PH Snorlax. And by people I mean XxSevagxX. But really Lunala is still a solid FC mon despite the meta adapting to it here recently. Not sure if it should rise any further though.
Solgaleo is a less passive and less bulky Registeel. You won't get mocked for using it just yet, but I don't think anyone fully understands why they put it on teams. Yeah it is a real-life Fairy resist and that's nice but it is still a weird choice in a para heavy meta. So this should probably drop.
Zygarde-Complete is in the same boat as Giratina, imo. Depending on the set, it either puts in no work and dies quickly or shuts down teams that can't do meaningful damage to it. I'm not sure where it belong but B seems fine I guess.
Celesteela should rise to B. Triage is a great late-game wincon still but other sets like PrimSea and Aerilate are useful in other ways thanks to a great defensive typing and lots of PP with Rapid Spin and Anchor Shot.
Magearna is a really nice option when you want a Pixilate mon that doesn't get 2HKOed by defensive Zama-C. Pixilate is definitely the best Magearna set around as it isn't incredibly passive like Fire-immune sets but its typing also allows for a decent Prankster and things like RegenVest. I have even seen Adaptability on the ladder pestering teams with Moonblast and Doom Desire. Nothing amazing there, but it shows this mon has versatility and might could rise to B.
Necrozma-Dusk-Mane has become the go-to Liquid Ooze mon recently. This is an interesting occurrence and I'm not sure what to think of it but it says a lot about how popular Strength Sap has become. Remember last gen when no one ran Sap or Parting Shot cause they were all terrified of Contrary? Good times...
Rayquaza is a pain to deal with. Mixed Aerilate sets are popular and take advantage of Flying-type STAB being very good right now. Zacian-C really did put a damper on the birds this generation for so long that most people forgot about them. But being able to break through Fur/Scales Zama-C with Boom/Speed and V-create is really useful and then you get into Triage sets with Core Enforcer that screw with Ice Scales mons. This is at least B and pushing into B+ maybe, despite missing some of the raw power that Kyu-B has.
Reshiram is a relic of gen 8 metas past. It feels much harder to use than Zekrom thanks to Fire immunity being more common than Electric but it still has the potential cause trouble with its STAB moves thanks to Core Enforcer and being slower than Zama-C. Not sure where I stand on its ranking though.
Yveltal still has trouble in this meta thanks to Xerneas but people are finally realizing that Yveltal doesn't play defense like it did in Gen 7. Triage, Band/LO Adapt, and mixed variants of these sets can do lots of damage given the chance. Banded Dragon Ascent just goes pretty hard on lots of the meta and Wicked Blow covers almost everyone else relevant but Magearna.
Zekrom has seen more usage lately thanks to sevag and city popularizing mixed attacking sets like Adapt LO and MGLO. It has good STABs for the meta but sadly Bolt Strike is not Bolt Beak. Still a very scary mon in the right (wrong?) circumstances and I think B- is a fine place for it still but could get behind B. Checking Triage is also handy.
Blacephalon can do some cool things in this para heavy meta. The fact that it can't really deal with Eternatus well is a big downside for it though and so is being an extremely frail Stealth Rock weak offensive mon. MGLO is a nice set to ignore rocks but lacks the power of the Adapt LO set. I think it is fine in C.
Calyrex-Ice is another mon that can do funny things with an unreasonably powerful move, Glacial Lance. I'm really not sure where Calyrex-Ice or Kyu-B would be without Glacial Lance. Remember when it survived a suspect test cause people were like "well... its like the only cool Ice-type move so...…. no ban??" like what was that? I still think about that a lot.
Cresselia doesn't need Eviolite to perform as a Prankster / utility mon and to me that is the only thing that keeps it above the other Eviolite mons in D rank.
Darmanitan-Zen has lost is niche in the current mixed attacker metagame and should fall to D if not out of the rankings entirely. Perhaps more exploration is needed here but I know for sure that its Fur Coat set is not what it used to be.
Ferrothorn stays relevant by "checking" Regigigas, Xerneas, Palkia, and Eternatus. It can't realistically check each of these threats at once and really doesn't have the stats to check either reliably without smart playing and support, but it can still perform under the right circumstances. I know this doesn't sound like high praise but I think C is still fitting for this monstrosity of a mon.
Golisopod is a strange pick in this metagame. Its typing still holds a niche but the rise of Magic Bounce and special attackers has been unkind to this mon. Poison Heal sets can no longer easily set hazards or spread burns. Fur Coat sets don't really check Gigas that well unless they run Topsy-Turvy but this means you have a very passive set. You can check Don but at the cost of being Imposter bait or a momentum drain. I could see this mon falling back to D for now.
Landorus-T has fallen off the map now that QT has taken to Spectrier recently. I mean seriously I can't think of many people who have used Lando-T outside of QT. I tried building with it not too long ago and wasn't very impressed. Yeah having Dragon Ascent means you don't
have to run Thousand Arrows but mons like Celesteela are on the rise and they give Lando-T some trouble. Perhaps this mon still has use left in the tank but I haven't seen any lately.
Melmetal is still used by MAMP and MAMP is cool. That's about all Melmetal has going for it at this point. I don't care where this is ranked but RIP to the former GOAT of the early gen 8 meta.
Pheromosa can still do some neat things with MGLO but it hates the recent popularity of Triage and -ate Extreme Speed and still isn't quite strong enough to pick up the big KOs on guys like Etern, Zyg-C, and Giratina. It is really fast though!
Registeel is unironically not bad. I just now won a room tour game using Prankster Registeel thanks to it actually being a Fairy and Flying resist unlike Zama-C, who can get cheesed by Xern and Triage folk. This could maybe rise to B- or B but I know people will hate to hear this.
Suicune exists, I guess? It does the usual bulky Water-type thing decently I guess.
Chansey has been seen occasionally on ladder and I've never been too impressed with it. It can be annoying at times though so I guess it can stay here in D.
Doublade isn't that good. It is still better than Aegislash though, but that really isn't saying much at this point. Every time I've used Doublade since Crown Tundra I've been extremely disappointed. I think it is time to give up on the Ghost/Steel family.
Dragapult can still do Normalize things and it is pretty funny watching higher level players bring it to tour games cause sometimes people sleep on Normalize and get wrecked. This can even happen on the ladder still, with the right support.
Dusclops does its job decently well. It is almost incapable of making meaningful progress in a game without running hazards but that means that Magic Bounce just forces it out. Entrainment is neat but again it just momentarily bothers mons like Xern and Gigas but makes no real progress unless its a 1v1 end game. I see no reason for this to rise.
Garchomp is another mon used by MAMP recently and that was cool. I really don't know if it belongs here but I'm not bothered by its presence and I don't think I'll ever attempt to build with it.
Giratina-O has been slept on for far too long. I don't want to hype it up too much here, but you can copy/paste the standard FC Lunala moveset onto this mon and have yourself a very nice set with two STAB moves. Trick immunity and powered up STABs from its orb is quite useful. One downside is the Speed Tier and I've mitigated this some by speed creeping with Timid nature but this does sacrifice some bulk. Offensive sets also have some potential cause things like Adapt Astral Barrage at +1 have a 6.3% chance to OHKO Xern lol! Moving up to at least C sounds good.
Heatran, no matter how hard it tries, will get completely obliterated by something. Ground, Water, Fighting, or even Fire moves all take their toll in some way depending on what set it is running. That being said, this mon has the potential to catch someone in a matchup and be very annoying.
Kyurem-White no longer exists. This should be removed from the rankings.
Lugia requires skill beyond my ability to use correctly so I can't speak on it. Ask cityscapes I guess?
Marshadow could be an anti-meta pick but it is still really hard to pull off with its lacking stats. I tried out Tough Claws LO recently with STABs and Triple Axel but wasn't too impressed.
Mewtwo can still show up with Psychic Surge Expanding Force and put a damper on priority attackers and Modest Eternatus and this is a decent niche to have, I think. Although RegenVest Zyg-C has been rising and Ice Scales Zama-C still soft checks this while forcing it to use Photon Geyser.
Regieleki is cool and I like the mon and its design. That being said, I miss Bolt Beak. The Galv Boom + Glance and V-create set is still cool on paper but I haven't played with it in a while. Might mess around with this mon some more soon but for now I don't think it needs to rise/fall any.
Slowking-Galar should probably drop out too. I tried using it once to check Etern but it lost to ImprisonForm Etern so that was fun.
Snorlax had a recent revival with Poison Heal Bulk Up to mess with Core Enforcer Ghost-types. I don't think it was enough to make Lax rise up but it definitely was enough to keep it in the rankings imo.
Spectrier has already been covered by myself and others but I'll raise my former proposal of C to B like the others have it.
Steelix is still on here? It gets 2HKOed by Zekrom's Dragon Energy with either LO or Adapt so that isn't good. I think this mon should drop out too cause there is very little reason to ever use it.
Swampert has no known utility in the current meta. Time to run Sap Sipper and meme on Sap/Volt Xern? (that is until you die from Boomburst in two seconds)
Thundurus-T is a mon I haven't personally used in a minute but the fact that it gets STAB on Oblivion Wing and Thunder Cage keeps it relevant as a niche Triage user.
Type: Null is a somewhat viable Pokemon. That's about all I can say about this one.
Umbreon still has a niche, surprisingly, but just barely. Spectrier's rise and even Lunala's make this pure Dark-type a sleeper pick on hard stall builds.
Urshifu-R has fallen on usage lately after it rose to relevance when DGZ and Zacian-C were still running rampant but I could see how it could be useful still. It still soft checks and offensively pressures several physical attackers in the meta with Fur Coat and its STAB moves.
Victini is a mon that I slept on for a long time. This tends to happen when I don't use something for myself and only go on hearsay. But dang it if this mon isn't spectacular at times. Choice Band V-create with Desolate Land has highly favorable rolls to OHKO both Xern and Gigas, which is pretty crazy to me. I think a C rank for this is feasible, especially considering how Darm-Z has lost its relevance.
Zacian is still rising thanks to the Tough Claws set poking holes in teams with its nice Fairy typing and fairly customizable moveset. The standard now is Fairy Multi-Attack, Fishious Rend, V-create but I could see things like Bolt Strike and Wicked Blow seeing use over time too. C or B- seems good for this as it is still item dependent to do most of its damage, whether that be its memory or a Life Orb.
Zamazenta does Tough Claws like Zacian does but is free to use a Life Orb and isn't tied down to Fishious Rend and V-create as coverage thanks to Close Combat. C sounds nice for this mon as it isn't quite as splashable as Zacian but is still a cool underrated breaker.