Gen 9 NU Offensive Swords Dance

Flamigo @ Fist Plate / Sitrus Berry / No item
Ability: Scrappy
Tera Type: Fighting
EVs: 252 Atk / 4 SpD / 252 Spe
Jolly Nature
- Swords Dance
- Close Combat
- Brave Bird / Acrobatics
- Roost
An offensive Swords Dance set Flamigo can use in Gen 9 NU. This set is used alongside Choice Scarf Munkidori, forming a good offensive core known as Flamunki, with Flamigo being free to use sets such as Swords Dance or Choice Band with Munkidori using Choice Scarf.
With Swords Dance, Flamigo boosts its attack stat to make it harder to switch into with its dual STABs that not even Ghosts want to switch into thanks to Scrappy. You can use the opponent switching out due to them being choice locked as well as the switches Flamigo forces as opportunities to setup Swords Dance. Flamigo's dual STABs pair nicely, since most Pokemon who can switch into Close Combat doesn't want to switch into Flamigo's Flying STAB, and vice versa. Brave Bird is Flamigo's powerful flying STAB that is useful to deal with checks to Close Combat such as Amoonguss, Toxicroak, and Sylveon. Alternatively, you can use Acrobatics for a safer Flying STAB that doesn't force Flamigo to take recoil damage. If you use Acrobatics, you'll need to be either itemless, or use Sitrus Berry if you want a little HP recovery before using Acrobatics. Roost provides Flamigo with reliable HP recovery to be able to last longer, and is useful to offset Brave Bird recoil damage if you choose Brave Bird as the Flying STAB. Tera Fighting is used to make Close Combat stronger.
Fist Plate allows +2 Close Combat to basically OHKO Diancie since Diancie doesn't use a physically defensive spread in NU, as it uses either Offensive Trick Room or Specially Defensive. Fist Plate also allows a +2 Close Combat combined with Tera Fighting to OHKO Bellibolt that hasn't Tera'd into a Poison-type:
+2 252 Atk Fist Plate Tera Fighting Flamigo Close Combat vs. 252 HP / 252+ Def Bellibolt: 440-518 (104.2 - 122.7%) -- guaranteed OHKO
Sitrus Berry is an option to help offset Brave Bird recoil damage and can help you live unboosted Cinccino's Tail Slap as well as unboosted Flygon's Scale Shot. You can also go itemless, but only if you use Acrobatics for the Flying STAB.