Bug
Scizor and Volcarona are two of Bug's most dangerous offensive Pokemon that returned. Volcarona in particular got more dangerous in the transition from SM to SS with the introduction of Heavy Duty Boots, patching up its own Stealth Rock weakness and Bug's lackluster hazard removal in order to sweep many types across the board, notably Steel which Bug teams struggled with beforehand.
Nice Choice Scarf user on Bug with its Fighting STAB and speed tier, can set Spikes too.
Speed Boost is nice for cleaning types but can struggle due to Bug's lack of good hazard removal, exposing its Rock weakness if it does not run Heavy Duty Boots, sometimes forcing it to forego Life Orb.
Dark
Extremely powerful offensive Pokemon, easily cemented itself into Dark as one of the best Pokemon on the type due to its good offensive stats, good coverage, and signature move in Wicked Blow.
Nice for fast Taunt and Stealth Rock, allowing Dark to run hyper offense a lot easier.
Generally a decent cleaner in late game scenarios against types like Dragon, Electric, Ground, etc.
Dragon
Toxic Spikes are great for patching up weaknesses against Fairy and Psychic which Dragon teams previously struggled against, and can Flip Turn to prevent momentum loss. A Poison typing gives the additional benefit of a Fairy neutrality too, and being specially bulky means it finds a lot of opportunities to do its job.
Electric
Magnet Pull is nice for beating Steel types and Steel itself is a nice defensive typing, making it a good tool to use on Electric teams.
Fairy
The introduction of Klefki means that Alolan Ninetales now struggles as an Aurora Veil setter, as it falls short of Klefki's superior defensive typing, access to Spikes, and Prankster. It is still viable for Snow Warning disrupting weather, but now much more niche.
Classic Klefki comes back to Fairy as the best support Pokemon the type has access to, setting down screens as well as laying down Spikes for the entire type to take advantage of. Its Steel typing is also great, providing a Steel neutrality, a Poison immunity, and many resistances across the board.
Belly Drum Azumarill works nicely against the types Fairy teams are typically weak to on top of being a nice sweeper. Fire, Ground, Steel, and Poison teams are all threatened by Azumarill once it sets up, now giving Fairy more leeway in those matchups.
Fighting
Like on Dark, Urshifu-Single Strike style is also one of the best Pokemon on Fighting due to its good Dark typing as well as its strong priority in Sucker Punch coupled with its good signature move and offensive stats. A strong Sucker Punch user is particularly nice for picking off Pokemon like Dragapult and Alolan Raichu which Fighting teams would otherwise struggle with.
Decent Psychic cteam and Choice Scarf user, has some other cool options like Knock Off and Spikes for Fighting.
Decent pivot with Regenerator but struggles to fit on Fighting teams in the long run due to their superior Choice Scarf users.
The oppurtunity cost is high for Urshifu-Rapid Strike Style considering Single Strike is much better on the type due to its Dark typing and STAB, while the type already has Keldeo for Water STAB.
Fire
Heavy Duty Boots makes Volcarona one of the most dangerous threats in the current metagame, as it now does not need to worry about being crippled by hazards, namely Stealth Rock. For Fire, it covers many matchups across the board due to its reliability, and even previous bad matchups like Ground and Dragon can potentially be swept by a well played Volcarona.
Electric Immunity as well as being a strong wallbreaker and Stealth Rock setter gives Alolan Marowak a nice niche on Fire teams.
Similar to Volcarona, Talonflame also appreciates Heavy Duty Boots as it allows it to preserve Gale Wings with Stealth Rock set and get off an emergency Tailwind, Brave Bird, or Defog much more easier. Should note that Tailwind is nice in an offensive based metagame, but Talonflame is niche at best even with these traits.
Flying
Cool Defensive typing and hazard setter that Flying teams appreciate.
Talonflame can run some niche Tailwind, Swords Dance, and Defog sets with Heavy Duty Boots but like Fire, its role on Flying remains niche.
Electric immunity but not good otherwise.
Ghost
Wallbreaker, Stealth Rock setter and Electric immunity in one, although it does face competition from Galarian Corsola as a Stealth Rock setter. Both of them are B ranked at the moment, but that can be subject to change as the metagame develops.
Ground
Nice Choice Scarf user with Knock Off, generally cool Speed control outside of sand.
Grass
Receiving Grassy Glide allows Rillaboom to preform as a strong and effective breaker in many matchups, with Swords Dance and Grassy Glide being a dangerous combination in particular.
Spore and the defensive typing is nice but otherwise it struggles to find a place on Grass teams, leaving it a niche option at best.
Ice
Cool offensive Rapid Spin user, but struggles with Avalugg's dominance due to its reliability and can be weak without boosts.
Normal
Normal's got its defensive core back again, and this time they can support the offensive Pokemon a lot better due to their access to Teleport, allowing them to pivot extremely well. Normal teams have been centered around its defensive backbone for generations, and putting both Chansey and Porygon2 at S again is no surprise here.
Decent special attacker with Choice Specs / Choice Scarf / setup, although losing its Z-move makes it inconsistent at times.
Choice Specs Boomburst hits really hard, allowing it to come in on passive Pokemon and fire off strong attacks.
Poison
Nice sweeper, beats the terrain types like Electric and Psychic nicely as well as others like Dragon, Fire, and Dark.
Good defensive typing with Spore and Regenerator allows it to form defensive cores nicely with Poison's other Pokemon.
Decent special attacker with Flip Turn but niche due to the faster special attackers Poison gets access to, namely Gengar. Hard to fit on most teams, which is why it's C ranked.
Psychic
Focus Sash Alakazam is incredible for Psychic teams as serving as a blanket check is extremely useful in an offensive based metagame.
Slowbro and Slowking are both nice Teleport users with good defensive typings and bulk. However, Slowbro's higher physical bulk is much more appreciated by Psychic teams that struggle to switch into Pokemon such as Excadrill, Galarian Darmanitan, and Urshifu-Rapid Strike Style have other specially bulky Pokemon like Celebi that make Slowking more niche.
Decent Rapid Spin user but fits on more specific builds.
A Poison typing allows it to absorb Toxic Spikes and gives it a nice Bug neutrality, but not much reason to use Galarian Slowbro over Slowbro other than that.
Rock
Tough Claws combined with good coverage moves allows Lycanroc-Dusk to be a nice offensive option on Rock teams.
Rock appreciates Tough Claws more, so base Lycanroc struggles to find a place even with Sand Rush, with Lycanroc-Dusk's priority in Sucker Punch and Sticky Webs being present.
Steel
Cool offensive support with Spikes and screens for more offensively geared teams.
Nice defensive typing but faces competition from Corviknight which can switch into Mystical Fire spam.
Magnezone is nice for trapping and pivoting with Volt Switch, but is worse than the B ranked Pokemon at the moment. We may plan to shift Steel's list up a bit, so Magnezone can potentially rise in the future.
Scizor's issue on Steel comes from the fact that it faces competition with a lot of other Swords Dance users like Bisharp and Aegislash, making it much harder to fit compared to Bug teams that appreciate its priority greatly.
Water
Urshifu-Rapid Strike style is a huge threat in the Monotype metagame at the moment, with its nice offensive stats, signature move in Surging Strikes, and ability in Unseen Fist, especially with rain powering Surging Strikes and Aqua Jet up.
Both offensive and Sap Sipper sets are viable, Sap Sipper sets are nice especially with Rillaboom's Grassy Glide threatening to sweep Water teams whole otherwise.
Great rain sweeper which is one of Water's main archetypes at the moment, effective against many types, notably Dragon.
Like on Psychic, Slowking and Slowbro are both nice Teleport users that can provide momentum. However, Slowking is preferred on Water due to its high special bulk, allowing it to check Psychic-type Pokemon such as Alakazam, Gardevoir, and Indeedee nicely, especially with the introduction of Expanding Force.
Toxic Spikes, Rapid Spin, and Liquid Ooze are nice niches to have but Tentacruel finds a hard time fitting onto teams with Toxapex being dominant.
Like on Dark, Sharpedo is a decent late game sweeper on Water as well, especially combined with rain boosting its Hydro Pumps, but has a harder time fitting on teams due to the abundance of more consistent rain sweepers Water has access to.
Decent Rapid Spinner but fits on specific teams.
Viable as a rain setter that can also use Perish Song, but Pelipper is preferred due to its U-turn pivoting, Ground immunity, and access to Defog.