Janice Biebrich is a teacher librarian in Winnipeg, MB Canada. She has built a terrific site about graphic novels. She has links for parents, teens and librarians.
Her list of recommended titles under Myths/Fables/Legends look like good bets for elementary libraries. I have read these two.
Rod Espinoza created The Courageous Princess a story with lovely art which is accessible to readers of all ages.
City of Light, City of Dark by Avi and Brian Floca originally came out in 1993. I have been looking for it for several years. It is back in paperback now that the graphic novel market is taking off. Two children try to unlock the mystery behind a subway token. Re-reading Kirkus Reviews, I notice that some of the dialogue is in Spanish as well as English.
The links in the Manga section will tell you everything you want to know about this popular genre.