Most of these are artists you have ever heard of, and that's what makes this significant; because I believe you'll reward yourself if you do go out and track these albums down. To help you swallow these down, I'll lay out for you the very particular criterion under which I decided makes these phenomenal albums:
(1) They accurately represent the band or artist's overall appeal. They would not want to leave these albums off of their resumes.
(2) They are coherent as a whole. They have the ebb and the flow and the continuity that makes listening to the work from the first song to the last a wholly satisfying experience.
If you do go through the trouble of getting your hands on these (which will be no small task, I assure you, as some of them have been out of print for a long time), I recommend you select one track from each and make yourself a very eccentric mixed disc (or playlist, if you're more modern leaning). You'll notice I even help you with your selections.
So without further ado...