Here's a list of my favorite punk bands and the side projects associated with them.
Bad Religion
Greg Graffin (Acoustic, 2 albums)
Social Distortion
Mike Ness (Acoustic, 2 albums)
Millencolin
Nikola Sarcevic (Acoustic, 4 albums)
Hot Water Music
Chuck Ragan (Acoustic, 4 albums)
Ignite
Zoli band (Acoustic, 1 album)
Alexisonfire
Dallas Green (Acoustic, 1 album, i think)