Unpopular/Unknow Albums

I recently got Penance Soiree from the The Icarus Line and noticed that many of the songs had less that 50k plays (all time) on Spotify, This got me thinking, what is the most unpopular album on the list. In this context I am using unpopular to mean unknown, rather than unliked (as in something like Captain Beefheart).

I'd be interested to know if others have found something less popular than The Icarus Line