Going to be a more brief post than my last VR posting because I dont see a point in repeating things as my opinions on most Mons has stayed the same. View that here :
https://www.smogon.com/forums/threa...and-metagame-discussion.3503019/post-10330506
Notable metagame developments:
The first 2 Mons have been thrust into the OU metagame through the collaborative genius of
giraffefromholland and
Shitrock enjoyer
, who as far as I'm aware have been innovating with these Mons for the past 2 years. Following Fruhdazis amazing run to finals in JI ( as well as the success his teams have seen being used in Mushi League heh), the ADV OU (zoomer) playerbase has happily subscribed to this new metagame development.
Registeel

A bulky behemoth that has been central to a lot of Mixed Offenses in recent times. Commonly running Seismic Toss, Thunder Wave, Counter and Explosion, Registeel can be a fantastic progress maker and act as a defensive glue for offensive teams due to its ability to eat up hits from both sides of the attacking spectrum. Registeel alone can struggle to make progress vs fat teams with access to lots of recovery. However by fitting it into Mixed Offenses, its teammates can make up for Registeels offensive shortcomings in these fat matchups. In offensive matchups, Registeel returns the favour by providing a solid pivot into a wide variety of attackers.
Modern Registeel teams frequently have Endeavour Swampert , DD Brick Salamence and Raikou, which make for fun teams to use. I'll leave the analysis of why these Mons work well together for someone else..
Pedro

As Vapicuno mentioned in his post, the boom of El Classico and other offenses that lack a special wall has created a gap in the metagame for Raikou to pounce into. Foddering DefGar, Roarless Zap, Celebi that clicks the wrong move, DefRachi ( can set up Body Slam variants outside of sand with investment), Raikou has a lot of setup opportunities and with no Blissey on these squads, 1 or 2 boosts is often plenty enough to wipe these teams from behind a sub. As mentioned for Registeel, the presence of Endeavour Pert, Registeel and DD Brick Mence on Raikou teams helps pave the way for Raikou sweeps as they help get the necessary chip on Raikou's checks.
Raikou hasn't just seen an increase in usage on Zoomer mixed offenses, it's been seen a few times on bulkier teams by players like ABR. Using funky sets such as Def invested Rest Raikou.
I have placed these Mons in the C tier, which is my cutoff for OU. If Medicham is OU since it can do work from lead every now and then, I don't see why Raikou and Registeel ,who are more consistent and see greater usage, shouldn't also be OU.
Jynx

This Mon is incredibly effective at getting value on Special Offense builds. Sacrificing itself to get rid of Tyranitar to allow for Weather Reset, putting Mons to sleep, sub CM ripping a hole into teams that lack a proper answer for Ice coverage, all off a solid 95 Base Speed. It can also utilise Perish Song and Mean Look , which in combination with Dug provides quite a unique way to trap Blissey. Quite an important detail is that Jynx builds usually use a Standard Dug rather than Beat Up Dug, which is a big +. Allowing these Special Offense builds to have a max Speed Dug gives them a way to answer+1 TTar and Raikou.
Jynx isn't a new development but I think it's pretty cool how this Mon has been optimised to get such great value even despite its paper tissue defenses and mono Ice coverage it runs. ( as far as I'm aware , HClat is the player who first optimised it in this way). I've been exploring the idea that Sleep may be the key to making SpecOff really tick, as the only SpecOff teams that I see play consistently are Jynx builds or that one Breloom team with Raikou Metagross. This leads me to think that Hypnosis Gar may be something SpecOff builds should look into..
Vaporeon

Offensively and defensively, Vaporeon has been seeing a lot more usage in the past year. Having the ability to pass 100+ HP subs , 110 SpA to throw off hard hitting Hydro Pumps and Ice Beams allow Vaporeon to pose a significant offensive threat that opponents must play carefully around. Tyros has long been a Vaporeon enthusiast (lol) and I've seen that River has been enjoying using it lately too. Players like HClat and Johnald have also used Vaporeon defensively on their builds, utilising its great bulk and access to Roar and Wish allowing it to be a defensive staple on teams.
Reginald Rock

Gigantic defense stat allows it to be a Physical Check and even a Pseudo Rock Resist without having to go heavy on defensive investment. Fruhdazis recent idea of using it with Choice Band and throwing off strong Superpowers is a great new way for Regirock to create progress, namely vs Swampert who has previously been a thorn in Regirocks side ( yes Boom can take out Pert, but landing that Boom is a task of its own). Hitting both Pert and Skarm in one click is amazing. Once Regirock has got sufficient chip on its targets, it can unleash a Banded Boom later on in the game to really solidify its impact on the game.
Regirock is a lot more common on Mixed Offenses recently, with Fruhdazi being a fan of it and using it in his builds, but also the likes of ABR also uses it, in builds like Kerts Spikes (TTar -> Regirock) and Slaking Offense.
Reginald Ice

Regice is the lonely sibling who's been left behind , not really featuring in the Mixed Offense trend that has been popular. I still wanted to mention it as I've found it fun to experiment with sets like Toxic BoltBeam where you Toxic Blissey then Spam Ice beam as they're forced to switch eventually, meaning an opponent has to eat an Ice Beam ( big 5 / aero squads often lack an ice resist) on another Mon which they really dont like. Speedy Regice is also cool, allowing you to get important chip / status. Something as simple as Booming a Milo/Suicune before it can heal up or Twaving a Metagross can be pretty impactful. Superpower and HP fire are also nice options to catch your opponent offguard. Psych Up is a gimmick imo and not worth running. Perhaps theres potential in using Regice as a Weather Reset user? Idk , I'll play around with it and report the findings when I get time.
On the topic of SpeedPass: I think in theory it does make Fat slightly stronger but at the same time I feel a weight has been removed from the builder when building Offenses. I can't and wont pretend that I miss SpeedPass anytime soon, RIP Bozo
That concludes my VR post this time. Vaporeon , Registeel, Raikou and Regirock have all had their careers revitalised in the past year with fresh new ideas allowing them to thrive in their niches. These Mons are are seeing consistent good performances in tour games , which is awesome to see. 22 year old metagame with new developments.. its peak.