I hesitate suggesting any artist, as someone here is bound to have heard of him or her, some even having actually heard his or her music. For instance, some have never even heard of Dave Edmunds, others are very aware of him (and his band with Nick Lowe, Rockpile). Same with NRBQ, and lots of other great bands.
But I feel safe in recommending a few:
- Van Dyke Parks. Brian Wilsons' collaborator (lyrics) on the ill-fated Smile album, his first album Song Cycle is like nothing else you have ever heard. Not Rock, not even Pop, it is indescribable. Not for dummies ;-) .
- Iris Dement. Not for those who have a low tolerance for Bluegrass or Hard Country, she is held in very high esteem by her contemporaries Emmylou Harris, Lucinda Williams, Joan Osborne, and many others.
- Julianna Raye. She hasn't made an album in many years, but her Jeff Lynne-produced Something Peculiar is fantastic.