Celesteela: While still a good wall, it's just not what it used to be. Its value stemmed mostly from checking Landorus-T's Flyinium Z sets, but since those have seen a decline, so has Celesteela. Krilowatt, who has recently seen more usage, is immune to Leech Seed and takes little from Heavy Slam and Flamethrower, also pressures it. Still, Celesteela is a good Tapu Lele check and can wear down switch-ins with its Leech Seed + Protect combination and good typing.
Blacephalon: It wasn't the Fire-type Choice Scarf user we were looking for. The ubiquity of Pursuit Colossoil and Tyranitar leaves Blacephalon hard to use, given that it can't realistically threaten these Pokemon. With Arghonaut and Toxapex acting as a full counters, and Gastrodon able to switch into non-Hidden Power Grass sets, Blacephalon has a hard time justifying its place on a team, compared to Heatran or Volkraken.
Mega Mawile: Although excellent on Trick Room teams, it fails to stand out when on standard team archetypes due to its slow speed. It has wide coverage that allows it to take on many bulky Pokemon, so it isn't dropping far, but it's a drop nonetheless.
Tapu Bulu: If it isn't obvious, Jumbao has given Tapu Bulu serious competition for a teamslot. Not only does Jumbao have a viable Fairy-type STAB move, it has a better speed tier and access to Wish. However, Tapu Bulu can still run a Swords Dance set, set Grassy Terrain for its teammates, and use Stone Edge for bulky Fire-types like Pyroak, which Jumbao would normally struggle with.
Volcarona: In the current metagame, Aurumoth's Psychic-type STAB allows Aurumoth to beat Tomohawk, Arghonaut, and Toxapex much easier than Volcarona. With the rise of Heatran and Mega Latios as well, Volcarona struggles with coverage, wanting Fire Blast, Hidden Power Ground, Z-Psychic, and Bug Buzz, but that doesn't account for Quiver Dance. Aurumoth can run a Psychic-type STAB, Focus Blast, and Blizzard to beat these threats instead, without worrying about missing out on a primary STAB option. Volcarona, due to its coverage problems and competition with Aurumoth, is dropping to A-.
Diancie-Mega: Although its coverage can dominate the metagame, Mega Diancie suffers from a few problems. Mega Crucibelle's influence in the metagame is having a signficant toll, not only because Mega Crucibelle outspeeds and KOs with a STAB move, but also competition for its Mega Stone, as Mega Crucibelle serves as a powerful Rock-type that also sports U-turn and an immunity to passive damage. Mega Diancie struggles deal with the omnipresence of Greninja and common Choice Scarf users as well, and if it makes a bad prediction, its frailty will usually result in an OHKO or a 2HKO. B+ fits because it requires some support to be very powerful, but it suffers from some issues.
Keldeo: 3 subranks might seem like a really far drop, but Keldeo just isn't what it used to be. Bulky Water-types like Arghonaut, Toxapex, and Gastrodon have risen to deal with Choice Specs and Scarf Volkraken, which inadvertently has damaged Keldeo's viability, as now it requires different types of Hidden Power to circumvent them. However, the problems do not end there, as Pajantom, Mega Latios, and Jumbao resist its STAB combination as well, further exacerbating its reliance on weak coverage moves like Hidden Power and Icy Wind. Scarf Kartana outspeeding every Keldeo variant does not help as well. Despite its role as a good offensive check to untransformed Greninja and Syclant, its weak coverage options, poor STAB coverage, and lack of recovery have really tanked its viability.
Latios: Mega Latios has risen to prominence mostly because competition for Mega Stones has somewhat decreased, as well as a hefty increase in Attack for Earthquake. There's more on Mega Latios in the Rises reasoning, but it basically means that any Latios set that's not Choice Scarf is basically outclassed. The problem is that Choice Scarf Latios is rather easy to take advantage of, is walled by Steel-types, and isn't reliable as a Defogger.
Naviathan: Ferrothorn's presence in the metagame hasn't helped the boat. While Dragon Dance + Guts is threatening, it struggles against most Steel-types and gets worn down pretty fast with burn damage. It's a capable sweeper, but it requires support to use fully and effectively, though under Aurora Veil it's pretty terrifying. Additionally, Calm Mind sets have been harder to use due to the rise of sturdy Water-type resists or immunities like Arghonaut and Gastrodon.
Rotom-W: Despite its access to Defog, the arrival of Jumbao and Pajantom did not do it any favors. Additionally, Zygarde opts for Substitute more, meaning that it can avoid Will-O-Wisp, and then Thousand Arrows beats it. Mega Crucibelle, Volkraken, and other heavy wallbreakers just overload it with damage, and the one Pokemon it should check well, Landorus-T, runs U-turn on almost every one of its sets and Flyinium Z less as well. Anything it wants to achieve offensively is basically outclassed by Krilowatt, which sports high speed to outspeed most Ground-types and KO them with Ice Beam, which hits more of them for super effective damage than Hydro Pump. It's a niche pick, but the role it fulfills is so small compared to other Pokemon that it falls into B-.
Sableye-Mega: With stall on a decline, Mega Sableye has a much smaller niche. It's the best Magic Bounce Pokemon in the metagame, but its low speed limits what it can achieve. Strong special attackers like Volkraken, Jumbao, and Heatran have to watch for Knock Off, but can take advantage of its turns using Will-O-Wisp, Recover, or Foul Play.
Skarmory: Although it has access to rare Spikes, Greninja and Ferrothorn are generally better setters, and it struggles against certain Zygarde sets unless it runs Whirlwind. It invites strong special attackers like Krilowatt, Heatran, and Volkraken in with its passivity, leaving it hard pressed to switch out. It's not unviable, but it's nowhere near top tier, especially given Celesteela's presence.
Tangrowth: While its access to Regenerator, Knock Off, and Earthquake can set it apart from Jumbao, it generally suffers from poor offensive presence. There's also the fact that can't crack open Arghonaut even with Giga Drain, and Tomohawk forces it out completely. Compared to Ferrothorn, who sports hazard control, and Jumbao, who sports reliable recovery, better offensive capability, and Wish, it needs to fill a specific shortcoming for a given team. Nevertheless, it can reliably remove items with Knock Off due to its longevity, scare off Heatran switch-ins with Earthquake, check Assault Vest Colossoil, and surprise switch-ins with a Sleep Powder from its physically defensive set, so it has a niche, just one that fits B+ better.
Tyranitar: While it can hit hard with Choice Band sets, Jumbao removing Sun with Drought sets and hitting hard with Moonblast otherwise really hurts Tyranitar's effectiveness. Even more unsettling for Tyranitar is Pajantom's ability to nuke it with Devastating Drake or Tectonic Rage before it can even move, while Colossoil threatens Pajantom with the potential Sucker Punch. Overall, it's still a good Pursuit trapper, but it suffers from a few problems with recent metagame trends.
Amoonguss: Like Tangrowth, Amoonguss faces problems when trying to compete with Jumbao for a teamslot. Amoonguss can check Fairy-types better, but realistically Jumbao checks everything else that Amoonguss checks but much better. It's still niche, but it fits more in B than B+.
Crucibelle: While Choice Scarf sets can handily check boosted Aurumoth and Volcarona sets, Trick a Choice Scarf to an unsuspecting Tomohawk, and pivot with U-turn, it suffers greatly from a lack of power. Head Smash hits for respectable damage due to its high base power, but Regenerator is best used to recover health from hazards and damage from resisted hits, not Head Smash recoil. It's niche as a Choice Scarfer is just really small.
Garchomp: How the mighty have fallen. General competition with Zygarde, who has higher bulk, Thousand Arrows, Extreme Speed, and Dragon Dance, and Pajantom, who also outspeeds the Base 100 Speed tier and packs Outrage and Earthquake as well, leaves Garchomp hard to use. Access to Stealth Rock sets it apart, but there are better options for Stealth Rock, including Tomohawk, Landorus-T, and Mega Crucibelle. It's still a niche pick, particularly for its Swords Dance + Stealth Rock + Z Crystal set, but it's not as viable as it once was.
Gengar: Although its STAB combination is pretty great, the influx of Mega Crucibelle has been a problem for Gengar, as it cannot fit Will-O-Wisp in addition to Focus Blast and Taunt. Additionally, Choice Specs can be easy to take advantage of, despite its power, Z-move eats the important team Z Crystal, and Life Orb doesn't help its frailty.
Jirachi: Even though it's a really sturdy Fairy-type check, it really struggles due to wanting 5 moves very badly: Wish and Protect for recovery, Iron Head for Fairy-types and flinch hax, U-turn to pivot (particularly against an incoming Colossoil), and Stealth Rock for general utility. Without one of these, Jirachi is mostly dead weight on a team, as it either gets worn down too fast or doesn't have the utility it wants.
Mew: Despite its access to Defog, its inability to deal with Colossoil makes it usually not worth running. Additionally, it can be rather easy to abuse its one-move coverage in Ice Beam or Psychic with any Steel-type, particularly Heatran. It's still servicable, but it's hard to fit onto teams.
Mollux: Recent metagame trends have not favored Mollux. Heatran, Mollux's biggest counter, has surged in usage, almost always running Earth Power or even Groundium Z to chip it down. While Mollux's STAB combination of Lava Plume and Sludge Bomb would otherwise be passable, Heatran's immunity to both of these forces Mollux to either run Hidden Power Ground or switch out. Additionally, the increase of Substitute Zygarde, Mega Crucibelle, and Pajantom means that Mollux gives up more free turns, especially when it fails to burn Zygarde or Mega Crucibelle. Toxapex, who sports similar resistances and higher bulk and a fantastic ability in Regenerator, and Gastrodon, with a similar Water-type immunity and a resistance to Stealth Rock, generally outclass it. Its weakness to Stealth Rock really shows as it slowly becomes more pressured by Specs Ash Greninja's Dark Pulse and flinch hax, as starting from 75% minimum compromises its ability to check it.
Gallade-Mega: Gallade-Mega suffers from being outclassed by three fronts: Mega Crucibelle can run U-turn to pivot, as well as dish out huge damage with its high powered STAB moves, and use Coil to set up, Mega Medicham simply hits harder without having to set up, and Mega Latios hits the same speed tier while using reliable recovery and Levitate. Swords Dance and Knock Off are the only things that really separate Mega Gallade apart, and while it can be a capable sweeper, the opportunity cost is generally too high, unless Mega Gallade is needed to be a specific sweeper for a specific team.
Gyarados-Mega: Using Mega Gyarados is worse than using Flyinium Z Gyarados in almost every respect. Despite the stat increase, STAB on Crunch, and Mold Breaker, it's not worth giving up the inability to break past Tomohawk, Pyroak, Jumbao, and Arghonaut, a handy immunity to Ground-type moves, and Moxie. A downtrend in Rotom-W and Mollux means Mold Breaker Earthquake and Waterfall aren't as useful. STAB Crunch can be useful for new rising stars like Mega Latios, but it's generally not worth running such an inconsistent sweeper.
Kingdra: Although it can still be a good rain sweeper, Volkraken and Greninja-Ash usually pull of the rain sweeping role a lot more sucessfully, while Mega Swampert and Hawlucha can pick up the slack with speed control. However, Swift Swim does make it devastatingly fast, so it's not completely outclassed, just more niche.
Mimikyu: Disguise can disrupt an offensive team's strategy and momentum, but it's mostly useless outside of that. It lacks power before setting up with Swords Dance, isn't particularly great at setting Trick Room and having other utility, and isn't the bulkiest Pokemon. Other Ghost-type sweepers like Revenankh and Necturna are generally better picks, making Minikyu's niche ever smaller.
Stakataka: While it might seem like a good Trick Room abuser, it's generally outclassed by Mawile. Defensive stops like Arghonaut and Tomohawk prevent it from reaching its full potential. It can still mutilate an unprepared offensive team when running an OTR set outside of Trick Room, but otherwise, it's not the best pick.
Serperior: Utility, speed, and Contrary Leaf Storm are useful, but Mega Crucibelle's recent surge doesn't help it. It's too reliant on Normalium Z offensively to sweep teams, and Leaf Storm sometimes doesn't cut it when it comes to mono-attacking utility sets. SubSeed, probably its best set, doesn't like Heatran walling it barring slow Leech Seed stall, most common scarfers beat it just by outspeeding, and slow VoltTurn like Mega Scizor make it difficult to set up Leech Seed.
Terrakion: Despite its good STAB combination, the rise of Mega Crucibelle, Mega Latios, Kartana, and Choice Scarf Landorus-T to prominence has left Terrakion rather difficult to use. Its inability to break Tomohawk even with Rockium Z and relatively poor bulk leave it hard to sweep and hard to switch in, and it faces a lot of competition from Mega Crucibelle as an offensive Rock-type. Priority users like Revenankh and Greninja-Ash leave Choice Scarf sets hard to use as well.
Bisharp: Outclassed by Colossoil in many ways, Bisharp doesn't do well in the metagame. Many defensive stops like Tomohawk, Arghonaut, Jumbao, Pyroak, Cyclohm, and Mega Scizor end up forcing it out more than not, and it's a terrible Fairy-type check despite being a Steel-type. Sucker Punch resists are common due to Colossoil's grip on the metagame, meaning Jumbao, Greninja, and Hawlucha check it offensively.
Gardevoir-Mega: Tapu Lele hopelessly outclasses it offensively, but it does have some utility options like Will-O-Wisp, Thunder Wave, Taunt, and Healing Wish that it can use. Additionally, its Pixilate Hyper Voice can foil a Substitute Zygarde's setup opportunity.
Heracross-Mega: Although outclassed by Pinsir-Mega in this role, it's one of the sturdier Colossoil checks and can break apart Arghonaut with a Skill Link Bullet Seed, without having to manage a huge weakness to Stealth Rock.
Latias: Although Choice Scarf Healing Wish is usable, it's worn down fast over time, doesn't hit especially hard, and is hard pressed as a Defogger to do its job and revenge kill with STAB moves at the same time, being even weaker than Latios.
Malaconda: Despite its access to Drought, it's now outclassed by Jumbao almost completely, even as its status as a Greninja-Ash check. That said, it can use Rapid Spin, preserve momentum with U-turn, and can be pretty annoying with Harvest.
Manectric-Mega: Although it has superior speed to Tapu Koko, it's rather one-dimensional. Even though it can pressure Grass-types with Overheat, most can see through this and double into an Overheat resist, meaning Manectric is at -2. Add in continual damage from hazards, average-at-best bulk, a rise in Choice Scarf Landorus-T, Krilowatt, Pajantom, and Mega Latios, and Mega Manectric becomes unable to do its job consistently.
Mantine: Being a very consistent Volkraken check with access to Defog sets it gives it a small niche for some balance teams, but outside of that, it's rather outclassed by other bulky Water-types.
Reuniclus: Although weak to Colossoil, it can set up in the face of many CAP walls and break past Arghonaut and Toxapex when unboosted. It's a niche pick, but it's a capable Calm Mind sweeper that's immune to status.
Sharpedo-Mega: While once a decent cleaner for Trick Room teams, Mega Sharpedo struggles to differentiate itself from other sweepers who have better bulk and more set up opportunities with better set up moves. It is unable to cover the metagame with 3 offensive moves, needing all of Crunch, Psychic Fangs, Earthquake, and Waterfall.
Slowbro-Mega: Once capable of sweeping with Calm Mind, the viability of Toxapex means it cannot set up reliably and gets whittled down by Toxic. Although it could run a 3 attacks set with Slack Off, Assault Vest Slowking usually pulls this off better, as it's able to better check Volkraken and Tomohawk. However, its titanic physical bulk allows it to check physical threats more easily, especially offensive Dragon Dance Zygarde.
Thundurus: Although Prankster Thunder Wave is a good form of speed control, its lack of recovery, weakness to Stealth Rock, and reliance on Life Orb puts it in direct competition with Krilowatt, which has only a little less Speed than Thundurus. It does have a good speed tier, but Thundurus-I can usually pull off Nasty Plot better with a double dance set.
Togekiss: A painfully awful Ground-type check, it loses to top Pokemon in the metagame, including Mega Crucibelle, Krilowatt, Pajantom, Flame Orb Facade Colossoil, Iron Tail Zygarde, and Tapu Koko. With most teams running a dedicated Flying-type resist for Tomohawk, Tornadus-T, and Hawlucha, Togekiss is really hard pressed to do much, relying solely on hax to get the job done.
Azelf: While Stealth Rock + Explosion is a good combination, Landorus-T pulls this off much better, as Swords Dance Explosion can actually dent hazard removers. Outside of this, Azelf really doesn't do much.
Breloom: The ubiquity of Tapu Koko's Electric Terrain makes Spore hard to use, and it's relative frailty shows when its typing suggests that it could switch into Colossoil and Zygarde, bringing almost no defensive utility to a team. Prominent Pokemon resist its STAB combination, like Jumbao, Tomohawk, Mega Latios, and Pajantom, and while they might mind a Rock Tomb, Breloom misses out on Swords Dance or Spore.
Diggersby: It might hit super hard, but it's rather slow and frail. Since it doesn't have many set-up opportunities, Choice Band would be its main set. There's almost no reason not to use Zygarde, Landorus-T, or Colossoil over this.
Dragonite: Salamence and Gyarados can pull off a Dragon Dance + Flyinium Z set better, due to their ability to snowball with Moxie, Gyarados's better typing and access to Taunt, and Salamence's superior speed. While Fire Punch, Earthquake, Extreme Speed are useful, Zygarde's Thousand Arrows compresses Fire Punch and Earthquake into one STAB move, and Zygarde also has Extreme Speed. Add onto the fact that Outrage is really awkward to use, and Dragonite is horridly outclassed at doing almost anything it would want to attempt.
Garchomp-Mega: Similar to Dragonite, Zygarde's Thousand Arrows makes its Earthquake + Fire-type coverage not as special. Its speed tier leaves it outsped by Jumbao and Tapu Lele, and picking Mega Garchomp means not picking Mega Latios, which has a much better Speed tier, can beat Tomohawk, Heatran, and Landorus-T, and has access to Roost and Defog. Colossoil also gives it competition as a Ground-type, sporting Rapid Spin, Sucker Punch, Knock Off, and Pursuit utility.
Kabutops: This really just has been here for too long. This was ranked when Mega Swampert was unavailable, and Mega Swampert really just does everything Kabutops wants to do as a Rain sweeper better. Rapid Spin Tomohawk or Defog Pelipper get the hazard removal done, while also acting as rain setters.
Kyurem: Ranked in Gen 6 for its ability to Pressure stall with Substitute + Roost, Kyurem has really fallen from grace. Although Ice + Ground-type coverage combined with Substitute, Roost, and Pressure sounds rather ideal, it's weakened rather quickly due to its weakness to Stealth Rock and reliance on Substitute.
Nidoking: Yes, it wallbreaks and has great coverage. However, it's main problem is speed, which is why Greninja and Krilowatt mostly outclass it. It's terrible as an Electric-type check, taking too much damage from Tapu Koko's Hidden Power Ice, Krilowatt's Ice Beam, and Magnezone's Flash Cannon.
Omastar: Although it can fit onto rain teams with Shell Smash + Waterium Z to overload Ferrothorn, other rain abusers like Ash-Greninja and Volkraken fit better onto Rain, and Volkraken, Choice Specs Pelipper, and Tomohawk can pressure opposing Ferrothorn anyway.
Pidgeot-Mega: The one saving grace that this Pokemon had over Tornadus-T, despite its lower speed and bulk, was its access to Defog. However, now that Tornadus-T has access to Defog, there's basically no reason to use Pidgeot-Mega.
Porygon-Z: Z-Conversion can turn Porygon-Z into a pretty powerful sweeper, but its susceptibility to faster Choice Scarf users after it sets up makes it hard to use. There's also pretty steep opportunity cost to not running a Z-move nuke on another Pokemon, or even other sweepers like Ghostium Z Necturna.
Scizor: Although Choice Band can still hit hard, Mega Scizor has begun to use Toxic sets to deal with the defensive threats in the metagame like Pyroak, Arghonaut, Tomohawk, Cyclohm, Zapdos, and Landorus-T. The same would translate over to Scizor, but Toxic doesn't mesh well with its offensive Band set, the best set it can run.
Scolipede: After the Baton Pass ban, Scolipede's only set was Waterium-Z + Swords Dance, but the set was never really that spectacular, particularly when trying to find a free turn to get its first speed boost. It's easy to pressure out with Ferrothorn, Tomohawk, Arghonaut, and other defensive Pokemon. Choice Scarf Greninja also stops it with Rock Slide.
Starmie: It's not that great of a spinner, with Greninja, Ash-Greninja, Sucker Punch Colossoil, Jumbao, Pajantom, and other offensive threats pressuring it from every angle. It can't run all of the coverage it wants to with Rapid Spin, and if it's not running Rapid Spin, it's directly outclassed.
Tentacruel: While it's bulkier than Starmie, it's a pretty bad Volkraken check and struggles to separate itself from Toxapex other than Rapid Spin, which is hard with a metagame with Colossoil and Zygarde. If it decides to run speed, it's not bulky enough, and vice versa.
Volcanion: Although it might super resist Volkraken's STAB moves, it doesn't have much to do offensively or defensively, especially when Volkraken could be run instead. Low speed leaves it outsped by Pajantom, Mega Latios, Colossoil, and other threats that can take it down with super effective coverage and bulk.
Blissey: Unless Blissey stall makes a resurgence, Chansey pretty much outclasses it.
Feraligator: This mon is outclassed by Naviathan, Gyarados, and other Dragon Dancers. Superpower lets it beat Ferrothorn easier, but it generally doesn't even have room to run that.
Mandibuzz: Dark / Flying isn't the best typing in the metagame, and it's basically outclassed by Tomohawk.
Porygon 2: Once a bulky Trick Room setter, it's not that great anymore with middling power.
Primarina: It can function as a Trick Room sweeper, but Crawdaunt pulls off the Water-type Trick Room niche much more effectively, and Jumbao, Slowking, and Mega Camerupt are better special attackers for Trick Room.
Talonflame: Although its Z-move can be hard to stomach, it's frail and doesn't hit hard before a Swords Dance boost.
SHSP
snake_rattler
Jho
Jordy
Mx
Rat With Wings
xavgb
Magearna
Heatran
Tornadus-T
Alakazam (Mega)
Ferrothorn
Garchomp
Ash Greninja
Celesteela
Greninja
Kartana
Landorus-T
Mawile (Mega)
Rotom-W
Tangrowth
Tapu Koko
Tapu Lele
Tyranitar (Mega)
Volkraken
Diancie (Mega)
Excadrill
Hawlucha
Latios (Mega)
Magnezone
Medicham (Mega)
Toxapex
Tyranitar
Volcarona
Weavile
Chansey
Gliscor
Kyurem-B
Latias (Mega)
Naviathan
Pelipper
Reuniclus
Sableye (Mega)
Slowking
Swampert (Mega)
Tapu Bulu
Zapdos
Amoonguss
Charizard (Mega-X)
Clefable
Gyarados
Jirachi
Pinsir (Mega)
Scizor (Mega)
Serperior
Suicune
Tapu Fini
Victini
Charizard (Mega-Y)
Garchomp (Mega)
Gastrodon
Lopunny (Mega)
Mamoswine
Manaphy
Moltres
Aggron (Mega)
Camerupt (Mega)
Crawdaunt
Ditto
Heracross (Mega)
Hippowdon
Hydreigon
Kommo-o
Mew
Slowbro
Slowbro (Mega)
Venusaur (Mega)
Pluffle
