IMO the greatest unknown (by the vast majority of even hardcore music lovers, including all y'all ;-) is guitarist Danny Gatton. He's well known amongst good musicians, such as Vince Gill, who nicknamed Danny The Humbler. If you like Bill Frisell (as you "should"), you will love Danny Gatton.
When David Sanborn had NRBQ on his TV show, he introduced them as "The best Rock 'n' Roll band in the world". How many here have heard them? One of the coupla best live bands I've ever seen & heard, and that list included The Who with Keith Moon, whom I saw twice.