Since Gamefreak decided to delay Pokemon Home, to pass my time, I decided to make a prediction as to how the meta will roughly look like. However based on the uncertainty of certain things, I have make a few assumptions.
1. Melmetal(this seems confirmed) is comming back, so is every pokemon with the unreleased tag on pokemon showdown
2. All pokemon that weren't banned in SS will be assumed to not be banned in this ranking
3. All pokemon that have been banned so far and pokemon that have been banned in SS will be treated as banned in this ranking
4. Even though it seems we can transfer pokemon with certain moves kept, I will make the assumption that everything that used to be thought as lost remains lost. For example, toxapex lost knock off and scald in SV so I will assume it stays that way for this ranking. Based on this document:
Home_Pokemon, the "movepool returning" section will be treated as moves lost.
Also, I would like to thank Neko and Astro Crossheart for helping me make this ranking. Huge props on them.
Without further ado, here is my ranking.
1.Flying 
Flying lost a tremendous amount of pokemon from SS to SV and now it has most of it back. The only difference between SS flying and SV flying is that your steel type is forced into being corv, which is fine but losing celesteela remains a problem. the highlight, as ususal, goes to landorus-t. No longer would you have to rely on a frail kilowatrel and dragonite to be your only electric immunity. Now, you have access to thundurus and landorus therian. This is compounded further by zapdos-g and tornadus-t joining. With flying as good as it is without those pokemon in SV, after home, flying will return to prominence with its boots spam and immunity to most entry hazards.
2.Dark 
The question with dark is why did it lose its number 1 spot. This is possibly the most contested ranking as, to be honest, both of these types deserve the number 1 spot. The main reason I ended up choosing flying #1 is because the only thing left to consider was the matchup against flying. This is where the debate began. Although it seems like nothing on flying switched into chien-pao, dark still has the problem of being forced to spam boots as it has no hazard removal. This means a corv lead is often not desirable as banded chien pao can break flying but is weak to rocks, but running boots mean you no longer have the ability to instantly threaten corv. Overall, because of dark's immense hazard weakness, I decided to place it at #2.
3.Steel 
With melm's presence and heatran returning, it seems as though steel is going to get back to #2 like in SS but herein likes the greatest problem, ferrothorn. Ferro shares a similar roles FROM A TYPING PERSPECTIVE to hisuian goodra. However, although goodra has more coverage, it doesn't have two things that ferro has, spikes and leech seed. So problem with steel is what I like to call the "6 pokemon syndrome." In order to use spikes, you have to run one of foretress, orthworm, or klefki(magearna is treated as banned). Foretress is a terrible waste of a team slot, klefki just has no purpose and steel would rather run tinkaton but even that is not too viable on steel. This means orthworm is the only reliable spiker steel has access to. Not only does it set up both spikes and steath rocks, but it also has an ability that actual counter gravity on ground. This is where the problem comes, you don't have enough team slots. You need to run the core(3 pokemon), treads(for speed control), and goodra-h for the spdef. Now you are left with one slot and you have to pick between melm, gambit, orthworm, scizor, etc. imo the best option is melm but that means you don't get to spike. All things said, steel is always going to be steel as long as the core exist. Even though they removed 2 steel birds, and remove aegislash, they replaced it with gholdengo and somehow left corv in. We know how obscene this core was back in SS so hopefully, with more limited options, steel can become a good but manageable type.
4.Water 
Just like steel always being steel as long as the core stays, water will always be water as long as a water ground exist. Most people can probably understand why water is here. Gren will always be gren, and peli + swift swim barras/other swift swim mons will always be great. In addition, water gets access to reliable spikes and offensive pokemon samurott-h. Sharpness boosted razor shells and ceaseless edges, with the utility of knock off, it looks to be a staple. But, it gets even better. Urshifu rapid got swords dance and punching gloves. Not only is it harder to check as after one sd, most pokemon die in front of rain boosted surging strikes. You can't use rocky helmet/rough skin to check it, punching glove ignores it. This means behind a sub, you can freely fire off attacks on pokemon with flame body and static. Although ursh-rapid might get banned, I don't think it's likely and water stays up at the top.
5.Ghost 
Ghost got spectier which has draining kiss and psychic. I don't want to gas up this type too much but spectrier + flutter mane sounds likes cancer. This is bolstered by the zoro-h running sub will o hex and hiding as spectrier makes ghost insanely good. However, similar too steel, it has "6 pokemon syndrome." Pult, mane, specs, dengo and zoro-h are mandatory, so you have 1 slot to pick between mimikyu(disguise + priority), skeledirge(defensively utility) and brambleghast(spikes and rapid spin). Although dirge is imo the best option, not running mimi/ghast is a notable weakness.
6.Fighting 
To quote crossheart, "sneasler is funny pokemon." This sums up fighting pretty decently. Sneasler is huge. It's signature move is the most broken garbage I have even seen. The number of times in room tours I used this thing and it helped me win a fight I had no business winning is insance. Next is hisuian decidueye. After long debates, I determined that this is the superior grass fighting on fighting over breloom and lillig-h. The main reason is the breloom and lillig-h can't touch dengo and because of scrappy, it actually threatens it. The loss of spore is pretty bad but the signature move of this pokemon is also, like snealser, very busted. Not only that, you have succer punch and shadow sneak to hurt faster pokemon. It has swords dance. Overall, a great for fighting.
7.Ground 
Ground got landorus. End of story. Alright, on a serious note, lando-t comming back is huge. Ground started the generation as one of the best types along side dark but slowly, its usage and win rate started to dwindle. The main reason that the balance playstyle becomes very weak to ice spam and as royalreloaded mentioned, gastrodon, clodsire, and quagsire often struggle to hurt certain flying types setting up behind a sub. What lando and ursaluna does is that it allows ground to pursue a much more hyper offense playstyle. With the rise of gravity sandy shocks, gravity HO like in SS might be comming back.
8.Dragon 
Hisuian goodra solved every problem dragon had. Problem with flutter mane? Goodra-h covers. In fact with assault vest, you only need max hp to be out of SPECS moonblast 2hko range and retaliate with heavy slam(in fact, max hp av only does 30 to 36), and unlike draglage, you who can't ohko mane, and need assault vest and absolute max spdef investment to be in 3hko range. Not only that, you cover specs ice beam from gren, as well as a bunch of ice type attacks from various pokemon. In gren's case, max spa gives you an ohko with thunderbolt. In fact the only pokemon with ice coverage that threatens you from the special side are the water grounds. In addition, sap sipper blocks spore and the steel type blocks toxic. I think this pokemon alone brought life to dragon who is STRUGGLING right now.
9.Fairy 
I actually don't have much to say about fairy. It gained enamorous which a lot of fairy teams in home room tours didn't even run it. Contrary superpower sounds funny but is too niche. You are better off run calm mind with cute charm. You might want to use diancie, but fairy needs its other members to function so diancie doesn't really have a spot. However, SR is nice you can run klefki over tinkaton. So all it all fairy is great, but the other types just got a lot of buffs so as a result, it's power level stays roughly the same why the meta as a whole got stronger. Mane and Valiant are well, still mane and valiant.
10.Electric 
This is just seems electric without koko and e-terrain. Zapdos is back, eleki is back and finally a good hazard remover for electric. Goodbye oricorio. We got iron hands and pawmot over zeraora, basically the same but with ice punch to hit lando-t. Electric was really strong in SS in part because koko could the terrain boost to alola raichu and other offensive pokemon and reliably get them in with fast volt switch and uturn as well as be a check to the dragon type. Now the e-terrain setter is pincurchin which is much worse at its job than koko. Without the terrain, electric lost a lot of the explosive power it had and it has a much worse time against dragons.
11.Bug
Just like how goodra-h saved dragon, kleavor saved bug. Bug is not a good type, but kleavor alone makes the type SIGNIFICANTLY better than before. Before, ghost could reliably solo bug with just a skeledirge. The main reason is that lokix needs band to actually threaten it and if dirge hits the will o wisp, it's over as it just slack off an slowly kill you with either hex/shadow ball. With Kleavor, you have to do this twice with dirge which gives bug a lot more wiggle room. Not only that, kleavor makes flying and fire more manageable(although the MU is still pretty bad). WyvernKing kept preaching kleavor saved bug. Although it doesn't save the type really, it did pull it out of the gutter which is huge.
12.Fire 
Fire gained volcanion and moltres. Even though moltres can't threaten pokemon like tran with scorching sands anymore, it can just uturn on it. Then there is volcanion, which helps a lot against water moves. However, fire is still pretty bad. Volcanion and moltres doesn't add enough. If we look at the top types, the only one it reliably beats is steel. The others it kinda beats or flat out loses. Fire still lacks a pokemon that can reliably beat fairies. It lost victini a huge nuke that helped in that department. In fact, steel stands even more of a chance than SS at beating fire which says a lot as to how bad it got. Then for those who asks about arcanine-h, here is me and Crossheart concluded: it's does help fire deal with its bad matchups at all. Almost every type has a ground/steel/fighting type and a dragon/water type. This means arcanine serves no purpose on fire.
13.Psychic 
With dark, ghost, and steel this good, psychic is not going anywhere. Without victini, you have no reliable way to beat pokemon like kingambit, as well as bug types. Mew and glowking are both huge, one is the best stall breaker imaginable and the other is an amazing special wall. Although the lake trio's signature sounds awesome, most types run a dark type which is doesn't help. This is worsened by the fact that you have to use
indeedee over tapu lele which is terrible.
14.Normal 
it gained ursaluna which sounds great but in practice it doesn't matter too much. It's just too slow. In fact, this is just kingambit(same speed) but with slightly worse defensive typing and much easier to where down because you are burned. Don't get me wrong, this is an amazing wallbreaker for normal, but it's just not enough at all. We've seen how normal does even with zoro-h, so with the tremendous power creep, normal just can't cut.
15.Poison 
This is possibly out more controversial placement. Posion is just too exploitable. The only hazard remover being glimmora is really sad because not only does steel block it, but it's a frail offensive mon that dies very quickly. Now let's look at the new pokemon added(those that matter). We have overquill, muk-a, glowking. That's it. Many might say sneasler but poison teams I ran into never ran it. It's obvious to see why. Poison is a very defensive type that often runs semi stall/balance. Plus, sneasler needs a lot of support to function well. It gets it all in fighting but not on poison. So, looking at the viable options, glowking is now a staple, and overquil and muk-a don't really work as neither have succer punch and although muk-a has knock off. It's just not enough. This type is one that is hurt by the stall nerf the most as in SS, that's what made it outrageously hard to deal with. Triple regen core(which it still has) + defog skuntank povided poison with insane longevity. Right now, its hazard removal option is terrible, recovery pp is halved, most pokemon especially toxapex losing knock off severely limits its ability to stall out the opponent enough where a cleaner can finish the job.
16.Ice 
I will keep this one short. Ice was bad with chien-pao. Home does not give it any better pokemon. Therefore it will stay bad. the only reason it's not last is because chien pao by itself carries the type. Without it, ice is worse type in mono, no question.
17.Rock
Arcanine-hisui and kleavor and the only noteworthy addition. Kleavor helps you against dark and arcanine-h helps you against steel. However, problems are still problems. The type has too many weaknesses like fighting, steel, grass, and especially water which neither additions actually help beat. The only reason it rose above grass is that it did gain access to pokemon that will help them against bad matchups. However, even though kleavor helps set up rocks, rock type pokemon already do that well witth things like ttar. All is all, just like royalreloaded said, the type lacks options and "all the pokemon available are easy to knock out and easy to switch into." Perhaps the only somewhat of an exception is arcanine-h which isn't enough at all.
18.Grass 
Getting rilaboom is great but the nerfs hurts it too much. Hisuian liligant also helps the type sweep more easily. Hisuian electrode helps a lot against the birds trying to wall the type. zarude is nice but meoscarada is almostalways better. However, no ferrothorn, and to an extent cradily, is still the largest problem. In SS, grass was an amazing anti-meta type as it beat water and ground really well and could hold its own against steel. Now, without ferro and with the rillaboom nerf, it can do none of that. The loss of cradily remove the only pokemon that helped against fire pokemon. With all this, grass, even though is my favorite type, if unfortunately the worst as well.
Overall, here is my tier list. I will not include Astro Crossheart and Neko's because they very much so resemble mine.
S+: The best of the best, virtually no weaknesses, tons of options
S: Very strong, typically has one exact flaw that can be played around, plenty of strong options
A: Great, has a few weaknesses that can be managed, decent number of options
B: Good, but could be better, has barely enough options to survive
C: Meh, has a few weaknesses which are very hard to play around, missing a few options
F: Bad, has too many weaknesses and losing matchups, have multiple flaws which are borderline impossible to play around, lack options in general
The whole point of monotype is to have fun. If you can dominate with a lower tier type, that's absolutely great. However fair warning, this is a prediction before the meta actually develops, so a lot of things might be wrong. However, I hope you enjoyed.
Thank you for reading.
Wanted to make a quick Frosmoth post too, honestly it feels alot easier to fit onto bug right now than at any other point that I can remember. The Bug Mirror with it usually is hot trash, and obviously it's not helping with Fire, but especially since bug has mon now to help with Fire (Kleavor), Frosmoth is able to shine a bit more for the matchups it does best in. Poison, Water, Flying - especially Flying as it's one of the best answers to Lando -I right now.
