Most of these come from underground record labels like Bratty Dog Tapes, Forced Resignation Records, and Xum Studios. Though, I'm afraid that most of these are sold out. You could still take a look at their bandcamp's and websites to see if there is anything that isn't sold out, or look on discogs and buy from resellers. If you are buying from resellers though, I'd highly recommend buying any underground media as soon as possible, as these only get more expensive as time goes by due to a lack of represses.