I'd like to use some of my experiences playing the post-tier shifts metagame, observations from 2025 RBY SU Discord tour, and involvement in RBYOMPL to break the ice on RBY SU with some analysis of how a lot of Pokemon are faring in the new metagame!
Choose your fighter
Most teams you'll see in this tier will overwhelmingly have a Fire-Water-Grass core anchoring the whole thing. This is the actual RBY lower tier where all three starter Pokemon are great, though there are some secondary Fire-types and Water-types that you can fit pretty comfortably onto teams thanks to the potency they have to pick up where their partners leave off. Horsea is a great sweeper while Wartortle is a good tank, and Ponyta can more comfortably clean up teams that have been weakened by Charmeleon.
Ivysaur is an already good Pokemon that has coveted access to sleep, something only matched by slower, less relevant Pokemon like Weepinbell and Venonat. You will want Ivysaur on borderline every team. Ivysaur's base 60 Speed, strong Grass STAB, and access to sleep makes slower Pokemon like Marowak, Lickitung, and Rhyhorn far more limited. Weepinbell's lower Speed makes it the inferior option, especially when it underspeeds Wartortle and doesn't Speed tie Horsea. Unlike with Fire-types and Water-types, type-stacking Weepinbell and Ivysaur isn't recommended.
Since Ivysaur is so good, Charmeleon distinguishes itself as a way to punish Ivysaur usage and ideally deter sleep. There's a rock-paper-scissors dynamic in the Charmeleon mirror that emerges, where you have Slash, Counter, and Substitute. Fire Blast's 30% chance to burn can be really nice to more reliably beat Arbok one-on-one, dampen the impact of Rock-types trying to intercept Charmeleon, and get a little bit of extra damage on incoming Wartortle or Charmeleon. 80 Speed is quite fast for the tier, and it lets Charmeleon consistently get a critical hit with Slash. Unlike Charizard, Charmeleon lacks Earthquake and Hyper Beam, which helpfully makes it a bit less overwhelming than it otherwise would be. Ponyta is a good back Fire-type because Charmeleon is so effective as a fast attacker outside of the late-game, and it can get really annoying with critical hits, Body Slam paralysis, and even Stomp cheese.
And with Fire-types being so good, Water-types thrive. Wartortle is one of the tanker Pokemon in the tier with one of the most convenient defensive typings, asserting itself as a solid pick despite its lower Speed and vulnerability to Ivysaur. Horsea is excellent as an Agility sweeper by overwhelming the fast Fire-types, and it benefits greatly from Fire-types weakening Wartortle and Ivysaur potentially dropping into Blizzard range as it tries to sleep a foe.
Pick your poison
Arbok was a fairly exciting new drop that hasn't really upended the tier as much. It's certainly not a replacement to the late Muk (RIP) or the even later Weezing (RIPIP), and has shown to be more comparable to the (post-Confuse Ray ban) Golbat, offering good Speed, well-rounded bulk, and fairly spammable moves for the tier. Arbok can beat many Pokemon one-on-one, especially squishy ones like Pikachu and Meowth, and Arbok's decent critical hit rate and rare access to Hyper Beam help it out. Unfortunately, burns from Fire-types and a lack of critical hits can sometimes leave it a little underwhelming. Arbok does benefit from Ivysaur deterring many slower Pokemon like Marowak and Lickitung that would hinder it more, so I do think it's a pretty good fit in the tier.
Golbat hasn't had its niche entirely stolen by Arbok, as it still notably outspeeds Charmeleon and the rest of the base 80s range, but it hasn't popped up as much.
Need for Speed
There's a good assortment of other fast attackers in SU besides ones I've mentioned. Meowth replicates some of Persian's role in UU as a fast attacker with Slash and some coverage moves, and it 3HKOes or 2HKOes most of the tier with Slash alone. SU also lacks many relevant bulky or Normal-resistant Pokemon.
Pikachu and Voltorb are pretty distinguished by their Speed tiers and positive matchups against common Water-types. Pikachu helpfully has Surf to deal with stray Ground-types like Marowak and Rhyhorn, while Seismic Toss is solid for Ivysaur. Voltorb boasts a Speed tier ahead of Ponyta and Golbat, and its Explosion can really help against squishier teams. Arbok's access to Earthquake does make running Electric-types a little tougher than in the last metagame, but they're still excellent as fast attackers.
Hitmonlee might be funny to see down in SU, even in a format that's notably hostile to Fighting-types, but here we are. Lacking Hyper Beam seals why Primeape is ZU and Hitmonlee is down here, but it's still sorely missing from Hitmonlee's moveset. Even in a tier that lacks Ghost- and Psychic-types entirely, Hitmonlee still finds ways to struggle. Ivysaur being on every team is not good news. A lot of people have been trying out Arbok and Marowak after the tier shifts, so Muk's rise (following the trade-off it did with Weezing previously) hasn't saved Hitmonlee. Hitmonlee's bulk makes it nearly as squishy as the other fast attackers in this section, and it's 2HKOed by the starter trio's special attacks. Its bad bulk is why Meditate isn't so easy to click, while burns don't make its life any easier. Even with Hitmonlee having a fairly good Speed tier by outspeeding Charmeleon, it's still just short of the base 90 Speed crowd. Charmeleon and Wartortle can even catch Hitmonlee with Counter, putting it in a tough spot and sometimes making Substitute better as a setup move compared to Meditate.
Diglett has a neat spot as a fast Ground-type given the potency of fast Electric-types and Meowth, but it struggles greatly with Horsea and doesn't appreciate Wartortle's long-awaited return. Diglett's awful bulk does not work in its favor, even compared to other squishies like Pikachu and Meowth, and Ponyta and Charmeleon threatening to hit Diglett as hard back as it hits them can also be a struggle.
Slow dance with me
Like I've said previously, a lot of the slower Pokemon in the tier, including new droops like Marowak, are really limited by the effect Ivysaur has on the tier. Marowak stands out for a strong EQ, perfect coverage with Blizzard, and the bulk and typing to take on Arbok. It's unfortunately victimized by the starter trio's strong matchups against it. Even Charmeleon and Ponyta can threaten to burn or crit Marowak and lessen its overall impact. I would not overhype Marowak too much, even if it's neat to have another fully evolved Pokemon in the tier, and a Ground-type at that.
Lickitung now holds the title of bulkiest Pokemon in the tier now that Muk has risen, not that it could ever replace Muk and its Explosion. STAB Body Slam and Hyper Beam are great tools, but Lickitung is challenged to get the most out of Swords Dance when it's running at base 30 Speed and slower than everything besides Rhyhorn and Geodude. It definitely enjoys Muk's rise taking away a panic button for it with Explosion on top of a Fire Blast burn fisher, and it still has the tier in a nice configuration with Hitmonlee being more middling and a lot of squishy Pokemon at the top. I've had mixed feelings about this Pokemon for a while, and that hasn't changed with shifts.
Rhyhorn was highly anticipated as a returning Pokemon to the tier, but the landscape of SU has changed. Checking Weezing used to be a great quality, but Rhyhorn doesn't have that key matchup anymore with both Weezing and Muk now being ZU. Ivysaur is a pain, Wartortle and Horsea are pains, the Fire-types can ruin Rhyhorn with a burn, and Pikachu has Surf. Rhyhorn is 3HKOed by Arbok's Earthquake and can't OHKO it back, inhibiting it as any kind of switch-in to the snake. Rhyhorn can be great if your opponent runs a lot of Voltorb, and Earthquake has great neutral coverage against the tier, but it's really hindered by its awful Speed and major 4x weaknesses in a tier run by Ivysaur and Water-types.
Clefairy differentiates itself from Lickitung with immediate paralysis, which can be really annoying for a lot of fast and squishy Pokemon like Charmeleon and Voltorb that rely on their Speed to be threatening. Clefairy can get really obnoxioius when hax goes its way between full paralysis, Psychic Special drops (something that can let it beat Arbok and hinder revenge killers), and potential Blizzard freezes. There's even Body Slam, Counter, and Seismic Toss in its movepool to boot. Clefairy is just unfortunately hindered by its own bad Speed, just above average bulk, and lower offensive stats.
Hidden gems
There's a couple of Pokemon in SU that people have been skeptical of, and there's a couple that I don't think are highlighted for their good qualities, so I'm going to give a little spotlight to each of them.
Goldeen might look a bit peculiar when Horsea is an option, but Goldeen's superior Speed to Ivysaur can be a major help if your Water-type doesn't have enough room to set up Agility. Water-spam is a good archetype on its own, and Goldeen adds a little extra Speed where Wartortle otherwise wouldn't. Both Water-types do well getting away with weakening each others' checks, although they have to be careful about Electric-types, Arbok, and Lickitung in these matchups.
Farfetch'd was dogged on for a long time, so as one of the few people to hold out a torch for it for a long time, I'm glad to see it getting some recognition! Rock-types are majorly limited in SU, so Farfetch'd is in a great position as a Normal-type sweeper. Base 60ish stats around the board aren't great, but Farfetch'd has great moves to make up for these traits. Agility and Slash turn Farfetch'd into a sweeper capable of 2HKOing or 3HKOing a good chunk of the metagame, and it's a bit stronger than Meowth. Farfetch'd is given positions to set up Agility pretty neatly once Ivysaur has popped sleep, and it doesn't run into Horsea's issue of being walled by Wartortle.
Doduo is another bird that takes advantage of the Ivysaur hegemony, offering Drill Peck for a more reliable 2HKO. Like Farfetch'd, it also has access to Agility, but 75 Speed comes up just short of being faster than Charmeleon+Arbok and the faster metagame, and Doduo's bad bulk doesn't do it many favors either.
Geodude might seem like a reach given my outline of Marowak and Rhyhorn's rough positions, but Explosion makes up the difference by making Geodude more effective at trading and punishing incoming Ivysaur or Wartortle.
Dratini is one more for the Agility pile, though Horsea's more impressive power with STAB tends to leave Dratini outclassed. Given its access to Thunder Wave, Dratini has some similarities to Clefairy, boasting a typing that offers neat resistances to Electric, Fire, and Grass. The flipside is that Clefairy is generally bulkier and a little stronger, has access to Psychic and Counter, and doesn't have an unfortunate Ice weakness against Water-types.
Hitmonchan is another quirky case. I've also described why Hitmonlee struggles, and most of its struggles are Hitmonchan's too. 50 / 35 bulk is atrocious, but Hitmonchan does have access to Agility to get it past Charmeleon and the squishy base 90 crowd. Unfortunately, it's mostly outclassed by Horsea and other Agility sweepers.
Machoke combines the issues of the tier's Fighting-types with the slower Pokemon for a very unfortunate cocktail. Unlike Marowak, it is helped a bit more by lacking Grass and Water weaknesses. There's a pretty neat collection of moves in its kit too between Counter, Earthquake, Rock Slide, Seismic Toss, Body Slam, and even Fire Blast for Ivysaur.
This is my personal VL as of today, though I'll still be readjusting it going forward with playing more, watching more RBYOMPL, and seeing how RBY SU Discord 2025 progresses. I haven't ordered these internally, though I would say that Ivysaur and Charmeleon are a slight step above Wartortle. Some of my earlier impressions of the tier, like Arbok being one of the best glues, just haven't panned out, though I was super close to making it A. I tend to be on the more optimistic side for Pokemon having niches in the tier, so my personal VL might look a little more packed than others'. I'm not an RBY god or anything, so take this all with a grain of salt, but I have been consistent with this tier longer than anyone and try to pay attention, discuss, and play regularly.
Everything in S feels mandatory to have or consider for your team and doesn't really have a true replacement for what it does; you can run Ponyta, but missing out on Charmeleon is a big hit when Counter+Slash are so good. The same goes for Wartortle and the other Water-types; I think Horsea and Goldeen are great sweepers, but Wartortle is such a fantastic splash for a lot of teams thanks to its bulk + Counter/Stoss, even if it slows a team down.
A ranks are great adds that round out the top three and usually buff up a team. Horsea is all that as an Agility sweeper, and Meowth, Pikachu, and Ponyta usually are the best fillers of the role of fast non-Charmeleon attacker. A lot of teams end up looking like starter trio + secondary Fire/Water + Electric + secondary fast attacker, so that's what this rank exists to display. Pikachu feels a step above Voltorb right now with Marowak and Rhyhorn testing being common, but it's very close, and I could easily put Voltorb back up in A.
The B ranks are for Pokemon that can be good but face competition, major flaws, or need a lot to go their way to put in consistent work. I touched on why Arbok might be surprising to see here, but there's often games where I've felt like running a different fast attacker would have been a better move for a team, especially when it comes up shorter against Fire-types, Wartortle, and the other faster attackers. Most of the meta-relevant slower Pokemon end up here for me because of the warping effect Ivysaur has on the tier. Diglett, Hitmonlee, Voltorb, and Golbat are all just a bit flawed as fast attackers compared to Meowth, Pikachu, and Ponyta IMO. Goldeen and Farfetch'd are cool as Agility sweepers, but Goldeen isn't on Horsea's level of power, and Farfetch'd needs a little more time to prove itself.
The C ranks display Pokemon that have a couple of nice perks but generally face a hostile meta, being overshadowed by something better, or just do their one thing relatively ok. Kabuto can sure check Fire-types in a vacuum, but it's slow and not much better off than Wartortle. I've already described the flaws of the slow Rock-types, Dratini, Hitmonchan, and Machoke above, so hopefully I don't need to elaborate on why they're in this bottom rank. Beedrill looks really neat to prey on Ivysaur, but Farfetch'd actually does a lot of its role without needing to extensively set up, and even Twin Needle fails to OHKO Ivysaur so... yeah. Shellder is neat for its access to STAB Water-type moves and Explosion in a tier without Ghost-types, but the Rock-types being irrelevant still isn't helpful to its case when it's running at base 40 Speed. Venonat and Weepinbell both have double powder, but Ivysaur's superior Speed is much more relevant than trying to spread paralysis.
Tl;dr: Ivysaur, Fire-types, and Water-types are all amazing. Use more fast Pokemon than slow Pokemon. SU rules.
Thanks for reading!
Arbok
Marowak
Ponyta
Rhyhorn
Wartortle
Charmeleon
Ivysaur
Horsea
Voltorb
Pikachu
Golbat
Clefairy
Lickitung
Meowth
Hitmonlee
Diglett
Doduo
Weepinbell
Dratini
Geodude
Hitmonchan
Machoke
Goldeen
Farfetch'd
Kabuto
Seel
Beedrill
Shellder
Has amnesia, but is steam rolled by razor leaf