Fables and
Sandman do both have some mature content (some violence, some scrabble-related), so you might want to check them out first yourself to see if any of it's a problem.
If she likes manga, she might like
Inuyasha, and if she's seen the movie
Labyrinth and liked it, there's a couple of manga that are sort of sequels. The first one is
Return to Labyrinth.
It's not a graphic novel, but if she's into fantasy, she might like Neil Gaiman's
The Graveyard Book and
Coraline.
Also, if you have a local comics shop, you might try talking to some of the folks there. Or, if you're not so fortunate, you might try contacting these folks:
http://www.sourcecomicsandgames.com/. They're local to me, and they're awesome. They might have some recommendations to offer as well.