List of darknet Tor websites
https://www.deepdotweb.com/2013/10/28/updated-llist-of-hidden-marketplaces-tor-i2p/
http://reloadedudjtjvxr.onion
markets: AlphaBay Market, followed by Abraxas and the Nucleus Market (source)
List of bitcoin tumblers
https://darknetmarkets.org/bitcoin-tumblers/
There are good factors for every person to mix their coins,
but for those which use Darknet Markets specifically, it is a need.