Besides our lovely, Ms. Kitty “Shadowcat” Pryde, these characters can phase as well!
http://en.wikipedia.org/wiki/Category:Fictional_characters_who_can_turn_intangible
Imperial Guard member, Astra
Heroes, er, not quite hero – DL Hawkins
DC’s Martian Manhunter
Thunderbolt member, Moonstone
DC’s Phantom Girl, who I was tempted to try to collect all of her appearances, but the Legion continuity is all over the place for my taste. I can barely keep up with Cameron Chase. and by keep up, I mean, nowhere close to owning 15 percent of her appearances.
The Host with the Most, Space Ghost. As well as almost all ghosts.
Avengers member, Vision
Spider-Man villian, Will o’ the Wisp – which is just fun to type
Plus various other characters that I don’t recognize in that link but these were the ones that I would have been able to rattle off besides that last guy.
What I like about DL Hawkins, is that we finally get to see what a villain would do with the ability to phase. Pretty much what you would expect but still, nice to see.
I prefer phasing over intangibility.
Shadow and Flame with Magik 