I made this to bring all the excellent free Underdark resources I could find together in one place. If anyone want their stuff removed, just let me know and I will take it down.
Found something else:http://somekingskent.blogspot.com.au/2009/09/2d-random-walk-generated-cavern.html
Sorry, not putting in anything from Kent. He's a sociopath.
Ok, how about this one then?http://recedingrules.blogspot.com.au/2014/03/lets-make-dungeon-map.html
Oh yeah, I think you should have a link to this blog from falsemachine.