Here's my favorite costumes for everyone:
Bishop: Original
Colossus: Age of Apocalypse
Cyclops: Old School (blue with yellow lines)
Deadpool: Original
Gambit: Original
Iceman: Age of Apocalypse
Iron Man: Age of Apocalypse (gray)
Juggernaut: Original (gray)
Magneto: Original
Nightcrawler: Age of Apocalypse
Jean Grey: Dark Phoenix (red)
Professor X: Original (yellow/black)
Rogue: Original
Scarlet Witch: Original
Sunfire: Age of Apocalypse
Storm: Age of Apocalypse
Toad: Original
Wolverine: 70s (yellow)