20 years ago I had several of the tribute CDs' that were mentioned here but at some point I realized I wasn't listening to them very much so I used them to barter with one of the few used LP/CD stores in my area.
The only one I kept was Where The Pyramid Meets The Eye (A Tribute To Roky Erickson) the former front man of the legendary 13th Floor Elevators. Intriguing interpretations by a very diverse group of artists & musicians, to say the least. 19 songs & imho nearly every one hits the bullseye. Highly recommended!