Full list of official 20XX character variations

(blank)= unknown

Fox - 20XX

Falco 20YY

Shiek - TU-TUXX

Marth - 20BC

Jigglypuff - 20ZZ/666XX

Peach - 20(.)(.)

Captain Falcon - 20GX

Ice Climbers - 2020

Dr. Mario - 20Rx

Pikachu - 20chu

Samus - 2388

Ganondorf - 20$$

Luigi - 2013

Mario - 2064

Young Link

Link - 20OoT

Donkey Kong - 20DingDong

Yoshi - 20eggseggs

Zelda - 20DB

Roy - 20OurBoy

Mewtwo - 20WoopWoop

Game and Watch - 2DXX

Ness - 199X

Bowser - Bowser - 20koopa

Pichu 

Kirby - 20XXX