First post in the OU VR, mainly based on World Cup.
Rises
to S: Heatran is one of the best glue Pokemon in the tier, able to soft check some of the best wallbreakers such as Kartana, Rillaboom, and Volcarona. Its ability to trap defensive Pokemon such as Toxapex,
to A+: Much like Kyurem, after the Magearna and Cinderace bans, Weavile has shot up to being the best late-game cleaner in the tier. Most of the Most of the Pokemon from A- to S cannot safely switch into it, as the ones that can fear their items being removed by Knock Off. Some sets have even chosen Icicle Crash over the stronger Triple Axel, to avoid contact effects such as Rocky Helmet from Corviknight and Buzzwole or Flame Body from Volcarona.
to A+: Urshifu has a unique speed tier, outspeeding pokemon such as Tapu Lele, Kyurem and Landorus-T. Fighting / Water coverage is fantastic, while U-turn is used to pivot out of problematic matchups against Toxapex. Future Sight support from Slowking helps this. Aqua Jet is also fantastic for picking off Volcarona.
to A+: I was a bit confused when this was dropped in the last VR, but the bird is the word once again. I've been using Heat Wave as the coverage, as I would rather have the better accuracy and sacrificing the Heatran and Tyranitar coverage, as in many scenarios, it would just be better to bring in it's teammates, while still taking advantage of Regenerator.
to A: Tapu Fini has emerged as a fantastic check to the rising Weavile and Urshifu, but has also seen its Choice Scarf and other utility moves it can use. Defog, Taunt, Knock Off, and Trick are all fantastic options to get fit what ever utility you would need on your team.
to A: Multiscale + Heavy-Duty Boots was an Arceus-send for Dragonite, now being able to take full advantage of its defensive capabilities without worrying about Stealth Rock, while also setting up with Dragon Dance. It is one of the best checks against Heatran, being able to use it as set-up fodder, and threatening to KO it with Earthquake. Ice Beam is also great coverage for opposing Dragonite and Garchomp attempting to check it.
to A-: Buzzwole is a fantastic blanket to many of the physical attackers such as Garchomp, Weavile, Rillaboom, and Kartana, further compounded by Rocky Helmet, while also having reliable recovery in Roost. Its coverage is extremely varied to deal with it's checks respectively, such as Earthquake for Toxapex, Poison Jab for Tapu Fini, and Stone Edge for Volcarona.
Drops/Abstain
to S-: While Slowking still deserves to be considered an S tier, and it's influence on the tier is very noticeable, but it is not on the levels of Landorus-T, Dragapult, and Heatran.
keep A: Volcarona is absolutely one of the most dangerous Pokemon in the tier to face, but we have seen much more Pokemon and coverage against it such as Tankchomp, Heatran and Stone Edge from Buzzwole. It also has horrible 4-moveslot syndrome, with Psychic for Toxapex, Bug Buzz for Tyranitar and Slowking, and Safeguard to guard against Thunder Wave and Toxic, so teams can adapt to it knowing what coverage it runs.
keep A: Rillaboom is mainly a testament to Pokemon such as Buzzwole and Dragonite, but it is still a fantastic. Grassy Glide is able to check many of the strong offensive Pokemon such as Weavile and Urshifu.
to B/B-: What does this even check anymore? Dragapult? Rillaboom? Dragapult can U-turn on it and bring in a threatening teammate such as Weavile, and Rillaboom can remove it's Heavy-Duty Boots, and also U-turn into a better matchup.
to lower: Sand has not had a great time, especially with the rise of Urshifu and Buzzwole, their shared weaknesses have become very exploitable. Specially Defensive Tyranitar is very passive, while Choice Band is very prediction reliant and very exploitable. Excadrill's poor bulk also leaves it susceptible to common priority such as Sucker Punch from Bisharp, Grassy Glide from Rillaboom, and Aqua Jet from Urshifu.
to UR: Don't use this. Walled by every Ground-type and outclassed by Tapu Koko for screens which has U-turn to provide momentum for teammates multiple times instead of sacrificing itself with Explosion, which is still relatively weak compared to other suicide leads such as Landorus-T or Mew.