There's a podcast I subscribed to called Darknet Diaries and they interview a bunch of people who ran online drug rings on the dark net and made money through bitcoin and the operation became fairly sophisticated.

The guy eventually got caught but only because of a snitch, not because of dealing in crypto or not covering his tracks well. I think it was episode #81. darknetdiaries.com

I also explore lots of survivalist and prepper communities and get some of my information from those sites.