Should try and avoid repetition.
First ABC (ignoring the second of any double-ups for a letter):
Archangel
Beast
Cyclops
Darkstar
Emma Frost
Fantomex
Gambit
Havok
Iceman
Juggernaut
Karma
Leech
Monet
Nocturne
Onslaught
Polaris
Quentin Quire
Rogue
Storm
Tyler Dayspring
Unus
Vargas
Weapon X
X-Man
Yuriko
Zaladane
Second ABC
Apocalypse
Banshee
Cannonball
Deadpool
Empath
Forge
Gambit (Again)
Husk
Iceman (Again)
Jubilee
Kane
Lorna Dane
Morph
Nightcrawler
Omega Red
Peterpan
Quicksilver
Revanche
Sabretooth
Thuderbird I
Ulysses
Vanisher
Wolverine
Yukio
Zach
Third ABC (so far)
Abyss
Bishop
Cannonball (Again)
Dani Moonstar
Emma Frost (Again)
Forge (Again)
Gambit (Third time now.)
Hank McCoy