Alternate costume (SSBU)/Mii Fighter
The Mii Fighters' various costume options are distinct from how other characters' alternate costumes work, as they can be purchasable from the Shop, found behind certain Challenges, found in treasure chests in World of Light, or purchased as Downloadable content.
As it was in the previous game, while Headgear can be worn by all Mii Fighters, the Outfits are more selective.
There are a total of 131 (80 + 51) different headgear, including the 'None' headgear.
Many of the hats that were in the original game were based off of hats present in StreetPass Mii Plaza.
There are a total of 143 (93 + 50) outfits, comprised of 53 (36 + 17) Brawler, 51 (29 + 22) Swordfighter, and 39 (28 + 11) Gunner outfits.
Mii Brawler Outfits
Mii Swordfighter Outfits
Mii Gunner Outfits
DLC costume trailers