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.

AffiliateWP - A powerful affiliate marketing solution for WordPress.

ShareASale - ShareASale has been in business for 20 years, exclusively as an Affiliate Marketing Network. Our technology receives accolades for speed, efficiency, and accuracy – and our reputation as a fair and honest business is well known within the industry.

Rakuten LinkShare - Building long-term, profitable partnerships between Advertisers & Publishers. Experience why Rakuten Affiliate Network (formerly LinkShare) was voted #1 Affiliate Marketing Network 3 years in a row.

eBay Partner Network - description here

ReferralMagic - Turn your users and customers into referral magnets.