21 Lists - Send and receive targeted, paid microtasks
Bitbounce - Charge unsolicited email senders a cryptocurrency fee
BitcoinGet - Earn bitcoin by completing tasks, answering surveys, watching videos, and more.
Launch - Free book featuring practical tips from top Product Managers
UserTesters.io - Earn money for testing websites, right from your couch.
Picoworkers - Earn money from doing short, easy tasks similar to Microworkers. Picoworkers is the best alternative to Microworkers I ever find.