You've seen at least some of Joe Pagac's murals around town. I just read that Joe has a map of his murals visible to the public on his website: joepagac.net/mural-map.
While I'm at it, I'd like to mention the map of hundreds of the murals on this blog. It's by far the most complete map of Tucson murals that I've seen. Co-editor David Aber maintains it. To see the map and how to use it, click on “Mural map” near the top-right corner of any blog page. Or go directly via http://map.tucsonmurals.org. (If your browser warns that map.tucsonmurals.org is insecure (it isn't) and you're concerned, here's a link direct to Google Maps: https://goo.gl/maps/0m9ja.)