I'm not sure how much Victini has been talked about, but it is quite the interesting threat in this meta. It's pretty versatile, and has a unique set of moves that allow it to pull off some sets it normally couldn't (or could, but would have less effectiveness).
V-create Spam (Victini) @ Assault Vest / Z-Move
Ability: Victory Star
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- V-create
- U-turn
- Bolt Strike
- Zen Headbutt / Filler
The main set you want to be using. Basically, hit something hard with V-Create and switch out, nullifying the boost. Bolt Strike for good coverage. Zen Headbutt for secondary STAB. If you don't need it, replace it with some coverage to hit Rocks or Grounds for SE damage.
This set is a great physical wallbreaker against most threats and enables a sweep for many mons, due to it essentially having 180 BP STAB that can pivot into another mon.
Special (Victini) @ Grassium Z
Ability: Victory Star
EVs: 252 SpA / 4 SpD / 252 Spe
Hasty Nature
- Fusion Bolt
- Fusion Flare
- Grass Knot / Energy Ball
- Flame Charge
This set is more prediction-heavy, but if you can pull it off, it can easily sweep teams. The combination of Fusion Bolt into Fusion Flare is very potent, pretty much hitting everything for insane damage. Fusion Bolt is very important to the set, as it is good Electric coverage, and after a Fusion Flare it has 200 BP. It also enables the next move in the link, Fusion Flare. Fusion Flare is a 200 BP STAB move with no drawbacks, so you don't have to switch out whenever you use it like you do with the V-Create set. Fusion Flare also enables Fusion Bolt to be the single best coverage move in the entire game. Grass Knot and Grassium Z are there to eliminate one of the most reliable checks to this set, Ground types. You can also use Energy Ball if you want more reliable coverage. Flame Charge is there so you can boost your speed so you don't get outsped, and is almost always the move you want to use first.
If you can remove Ground types, the combination of Fusion Bolt + Fusion Flare enables this Pokemon to be one of the most potent sweepers in the game (and it doesn't even need setup!)
Z-Celebrate (Victini) @ Normalium Z
Ability: Victory Star
EVs: 4 Atk / 252 SpA / 252 Spe
Hasty Nature
- Blue Flare / V-Create
- Bolt Strike
- Celebrate
- Grass Knot
decent mixed sweeper
So Victini is pretty versatile and interesting. Definitely worth using.