This looks like a cool meta, my thoughts:
Regulate (Normal)
Staraptor, Diggersby and Porygon-Z are now incredibly threatening
Actually, Porygon-Z was the only one of those that was decent, though admittedly this was pre-ORAS and ORAS did a lot to make Diggersby good. Staraptor was... yeah, Reckless Double Edge hit hard, but
everything in the meta hit hard.
Gladiate (Fighting)
Guts Conkeldurr with a 182 BP STAB Façade will destroy worlds.
Lucario was good stuff, as Fighting Extreme Speed backed by Swords Dance with a Focus Sash could sweep entire offensive teams by itself, and the meta was offensively slanted. Conkeldurr was mostly good as a wallbreaker, which... is okay, but not amazing when the meta is so offensively slanted.
Aerilate (Flying)
Noivern with STAB Boomburst will wreck everything. Tornadus-T can try a Bulk Up set too I guess
Noivern was actually underwhelming. Not that it doesn't have
some use, but it wasn't that great.
Tornadus was actually usually better off running Defiant Incarnate. Intimidate abusers were extremely popular, in part due to how Physically slanted the mete is, and Defiant abuses that, while getting use out of Regenerator was hard when so many things would OHKO you if you weren't an actual wall.
Toxicate (Poison)
Nothing OU relevant has Poison as its primary typing
Crobat was kind of neat, actually, and a good partner with Lucario since it could U-Turn out as the enemy switches in a Steel type and now they're being threatened with Fighting Extreme Speed. This would be even more true nowadays, as Aegislash hadn't been banned yet when this was last OMotM. Since the meta is offensively slanted, it wasn't unusual for a team to have no Steel types, either, so immunity to Poison was a more manageable concern.
Beyond that, yeah, not a lot of payoff. Tons of Poison types are secondary Poison, Arceus is the only Poison type to get a boost on the Special end, and Poison is an awful type
Terrate (Ground)
Landorus-T can take a leaf out of Mega Glalie's book with its nuclear STAB Explosion. Gliscor can abuse a powerful STAB Façade with Poison Heal.
Gliscor had no real to
not run Facade over Earthquake, certainly. Unfortunately, Gliscor has severe 4MSS, and it wasn't unusual to drop Facade because stuff like Knock Off was more reliable. In practice the main thing Gliscor gets out of the meta is that it's one of the few things wall-y enough to tank various key threats in the meta -like Landorus-Therian.
Landorus-Therian with Explosion is funny, and I saw the occasional suicide lead that dropped Stealth Rock and then Exploded, but it was uncommon, especially since Ground immunity was fairly popular, in part to deal with the likes of Excadrill.
Sedimentiate (Rock)
Godsend on every OU relevant Rock type
One of my favorite things for a bit there was actually Omastar. It gets Wring Out, which when the target has full health is 121 BP before the -ate bonus, more than doubling Omastar's Special Rock offense. This often really threw people, letting it get a KO or two before it went down. Main flaw with it was priority was common.
Barbaracle also gains an impressive amount of viability, because Tough Claws -ated Frustration is something like 170~ BP compared to Stone Edge's 100 BP. Nasty stuff.
Terrakion is notable for
Rock type Quick Attack. Among other points, bulky Talonflame would be outsped and OHKOed. It was also decent at revenging against a fair number of key threats, like Mega Aerodactyl (see: Barbaracle, but no Shell Smash) and was just generally great stuff. Bonus points: Justified is more relevant with stuff like Dark Fake Out Weavile being a thing, a thing you can then kill with Quick Attack and if they're stupid enough to Quick Attack you they've given you a free +2 in the process. Good stuff.
Diancie is helped by a decent amount, but not
that much. Physically, it might
still prefer Diamond Storm, and on the Special end Nature Power isn't
that much of an improvement over Ancient Power.
Infestate (Bug)
Heracross could do the same as Conkeldurr. Scizor doesn't need Bug Bite anymore. Scolipede doesn't need to risk a miss with Megahorn.
Scizor can also run Quick Attack, and did at times, letting it take out some fast Psychic and Dark threats that had the coverage to incinerate it otherwise. Occasionally it would run Feint instead, to push past enemy Quick Attacks (Such as Weavile, if Scizor had been weakened enough), though this was less common as Terrakion was by far the most common Quick Attacker and it made more sense to hit it with Bullet Punch.
A bigger payoff was actually to Forretress, as it gained unblockable Rapid Spin. Delibird, Avalugg, Kabutops, Armaldo, and Cryogonal were the only other Pokemon to gain
truly unblockable Rapid Spins (Ignoring Shedinja, for which only Kabutops and Armaldo qualify as unblockable spinners), and they're all less viable than Forretress. Excadrill's Rapid Spin is actually
easier to block, for instance. There are other Rapid Spins that are
difficult to block, like Starmie, but not impossible, and immunity Abilities were a lot more popular in Metagamiate in general, and therefore so were the Pokemon with them. Forretress stood alone as a spinner the enemy couldn't carry the right Pokemon to block.
Spectrate (Ghost)
Only OU relevant Ghost is Gengar who can't make use of this ability unless it runs Uproar.
In addition to Mega Banette actually being surprisingly nasty... well... if you look at Ubers you get Hyper Voice Giratina...
... yeah okay you're pretty close to correct on Ghost. Sableye is easy to think it's relevant, but it's Dark/Ghost.
Metallate (Steel)
Mega Metagross will destroy worlds with its 132 power Tough Claws boosted STAB Return. Jirachi will also like having a STAB Body Slam stronger than a STAB Earthquake.
Pre-ORAS, Rock Polish Rock Head Aggron using Double Edge and Head Smash was able to sweep teams once enemy Steel types and Fighting priority was dealt with. (Technically Gliscor and Flygon get Ground Quick Attack, but nobody ever ran it, and with Flygon getting Boomburst now...) It was great stuff.
Pyrate (Fire)
Physical Fire types love this, as they now don't have to have Flare Blitz's recoil. Entei and Arcanine now have STAB Extreme Speed; Charizard X gets Tough Claws boosted Return
Pyroar was...
almost okay, too, thanks to its access to Hyper Voice. It could kill certain Substitute stallers -and Substitute was good for cutting down on the extreme damage being thrown around- that were otherwise not overly afraid of Hyper Voice spam. (Mostly Steel types trying to Sub-stall)
Hydrate (Water)
Say goodbye to the weak Waterfall - now (Mega) Gyarados and Azumarill will be total powerhouses. Mega Swampert in Rain can outrun almost everything and destroy things with its Rain boosted STAB Return. Politoed also gets Rain boosted Hyper Voice.
Politoed was a goddamn
monster and almost always either ran Choice Specs without even bothering to be a proper rain team or would frequently stay in and vaporize whatever the enemy's lead was before it switched. In general rain was surprisingly viable, with stuff like Swift Swim Hyper Voice Seismitoad and Ludicolo, Swift Swim Physical attackers, etc running around.
Germinate (Grass)
Poison Heal Breloom gets an insanely strong STAB Façade. Swords Dance Mega Sceptile could be extremely threatening.
Breloom was actually bad and desperately wished it was Fighting/Grass rather than Grass/Fighting. Its Facade was easily walled, and it had to fear a lot more OHKO and its sub-seed sets had to fear Hyper Voice much more often.
One of the only Grass types that really benefited was Ferrothorn no longer fearing a miss on Power Whip.
Generate (Electric)
Eh...no good users
In addition to Jolteon that other people have covered -and it was
quite good, thanks to its ridiculous Speed tier- Physical Electric types were, in general, a lot better, and in particular could actually get away with Focus Sash, and Focus Sash was incredibly good in the meta. Pikachu, in addition to Fake Out and Extreme Speed, got Last Resort, and could actually sweep poorly prepared teams with Fake Out+Last Resort. Seriously.
Psychokinate (Psychic)
Mega Gallade now has a strong Psychic STAB to go with Close Combat.
Espeon was actually a fairly impressive Hyper Voice abuser, once you got Steel types out of the way. A gimmicky Mew set was Fake Out+Last Resort. Obviously that was hard-stopped by Dark types, but it was surprisingly threatening. Victini was also kind of interesting, able to run Life Orb V-Create and then use Quick Attack to finish off Focus Sasher or dish out egregious damage to attempted revengers like Mega Aerodactyl.
Refrigerate (Ice)
Mamoswine absolutely wrecks
Actually, it barely benefited. It almost never wanted to run Frustration over stuff like Ice Shard. There were more-or-less no Ice types that actually benefited enough to become viable -out of ones that got Refrigerate, anyway.
Slaviate (Dragon)
A godsend to physical Dragons, as they don't need to use Outrage anymore. (If it hasn't been banned) Kyurem-B loves this.
Regular Kyurem getting Hyper Voice was cool too. A small, flat upgrade.
Tenebrate (Dark)
Weavile gets a really strong STAB if you don't mind giving up Knock Off. Hoopa-U's Return hits insanely hard.
Actually, the thing that set Weavile apart was Dark Fake Out and Dark Quick Attack. It usually still ran Knock Off as a primary attack if it ran a "generic Dark attack" at all. Dark also has an unusually large number of Hyper Voicers (Including the likes of Hydreigon), making its Special game a lot more threatening.
Pixillate (Fairy)
All it really does is give Clefable a stronger STAB.
And gives Togekiss an amazing Special STAB (Hyper Voice) or Hustle Banded Pixispeed (This happened, and was actually decent, among other points used as an answer to Dragonite prior to the ban), lets Sylveon run Cute Charm for free, and dramatically improves Slurpuff's primary STAB. It was actually vaguely usable
before ORAS gave it Drain Punch and all!
Plus, Double Edge Magic Guard Life Orb Clefable was a thing, and actually decent.
