DLSite : A Japanese gaming site (available in English and many other languages) that specializes in "doujin" independent games from that country, nearly all digital downloads at lower prices. Has two different "adult" and "non-adult" sides to the site, you need separate affiliate accounts for each of them (the "adult" portion of the site has "maniax" in the URLs). Pays 7.5% to 12% on referrals that lead to a sale.
Itch.io : Popular indie game digital distribution platform that carries all types of games, including adult. Anyone who creates an account can refer sales for about 10%, but an application is required to access the more advanced portion of the program that provides free review copies of games.