The introduction of player-generated costumes (_in Tekken 5?_) kind of ruined Tekken for me though, as even in single player modes you're now confronted with semi-random garbage outfits and palette swaps instead of the expertly crafted, diverse, interesting outfits of the previous games.
Starting with Tekken 4, Yoshimitsu has an alternate costume that is an homage to Genpei Tōma Den AKA Samurai Ghost, a Namco arcade / Turbografx game in the same genre as Konami's arguably better known Getsu Fūma Den.
I‘m not sure getsu fuuma den is the better known game since samurai ghost has TWO games (samurai ghost being the 2nd) and and started in arcades, where getsu fuuma den was a - I don’t want to say clone, but very close homage to the earlier genpei fuuma den (and its famicom/PC engine ports) so if it is indeed better known that sure sucks for 1980s namco!!
Anyhoo costume alts - I sort of like that hey brought back athena's warrior costume for neo geo battle colosseum
https://youtu.be/PguxMlmZTpc?t=49
but the best costume alts will always be the custom tekken ones I reckon.
https://www.youtube.com/watch?v=rdCohteFEKU
To kick it off, I figured I would share one of my favorite Ryu variants. I remember thinking it was pretty rad that you could finally choose alt color schemes in _Super Street Fighter II_ for the SNES and this orange/blue combo was especially cool: