ClickBank - ClickBank is a secure online retail outlet for more than 50,000 digital products and 100,000 active affiliate marketers and are consistently ranked as one of the most highly-trafficked sites on the web.
Refersion - Seamless influencer tracking system for online retailers.
Commission Junction - CJ Affiliate by Conversant (formerly Commission Junction)
Post Affiliate Pro - Post Affiliate Pro is the #1 ranked affiliate software, trusted by more than 27,000 companies worldwide. Start your affiliate program now.
eBay Partner Network - description here
LeadDyno - Lead Dyno - Affiliate Tracking Software