Magik vs Satana or Helstorm
Iceman vs Odinson
Rogue vs Thor (Jane Foster)
Selene vs Morgan le Fey
Selene vs Hela
Monet vs Psylocke
Rictor vs Quake
Cuckoos vs Quentin
I cant say I'm fond of hero vs hero events but there are quite of few match-ups which could be entertaining.