RolStoppable said:

Another outlier is Super Smash Bros. Ultimate where the popularity of the game has caused the introduction of a second fighters pass, but the new fighters still have to be purchased as a package as individual purchases are not possible.

You can buy each of the five "challenger packs" included in the first fighters pass seperately. I imagine the second fighters pass will also offer it's six pieces of content as individual purchases too.

LTD: PS4 - 125m, Switch - 110m, XBO - 51m

2020: PS4 - 9m, Switch - 22.5m, XBO - 2.5m, PS5 - 4.5m, XBX - 2.8m