Mii Fighters can be created directly in Smash Ultimate, which is handy since you can't create them on the Switch menu. Mii outfits are still collectable in Switch.

All custom moves have been removed with the exception of Mii Fighters which have the same custom moves as in Smash 4. Their custom moves are edited in the settings used to create Mii Fighters.

Spirits can be used in local multiplayer matches and the World of Light. They can add a larger variety of buffs, stats modifications, and even nerfs. They function somewhat similarly to stickers in Brawl but with a larger range of effects and they can be removed from a character without drawback (removing a sticker causes you to lose the sticker).

In addition to spirits is Dojo training. There are various Dojos obtained through playing the World of Light which each providing a range of stat modifications that can be applied to spirits, for example increased jump and weight but decreased speed and attack. One Dojo (Slowpoke) can remove other Dojo stat modifications.

Amiibos function similarly to Smash 4. Any amiibo for any of the playable characters, including those for Smash 4 and those not created for Smash, work in Smash Ultimate: a list of these amiibos is here. Certain amibos also grant you a spirit that corresponds to the amiibo, also contained in that list. Contrary to the rumours, amiibos don't unlock characters instantly.

In a real Smash Ball, the vertical stripe of the "brethrens' cross" is thicker than the horizontal one, and it's further away from the center of the symbol. In a Fake Smash Ball, the thickness of the stripes is reversed.

This can be harder to distinguish if the ball is rolling around on the ground, but even then it can become clear that the fake cross is the mirror image of the real.