There are currently a few bands with the name avantgarde, regardless of how it is actually spelt. One well-known band is an indie rock band from Spain http://en.wikipedia.org/wiki/Avantgarde_(band) and another is a booming rock band from Brunei.
Another one is a german producer creating lo-fi electronic music with influences of ambient, rave, glitch and other styles.
http://avantgarde13.bandcamp.com/


Read more about Avantgarde on Last.fm.