The Surfer SEO Affiliate Program offers a a recurring Commission structure
Lasso has an affiliate program that offers a one-time, $49.00 commission when the first payment from a referred customer is received.
All In One SEO is a WordPress Plugin made by Semper Plugins. The All In One SEO Affiliate Program is part of the Share A Sale Network.
Spyfu is a popular keyword tool where you can look up information about a keyword or topic that can lend to marketing decisions. The Spyfu affiliate program offers recurring commissions with a 40% payout for life.
SEOPress has an affiliate program. Because it is a subscription service, you have the opportunity to earn recurring commissions.
Long Tail Pro has an affiliate program with the Share A Sale Network that includes a two-tier (sub-affiliate) link as well. Promote Long Tail Pro and earn through their affiliate program.
SEMrush is an SEO Audit tool and so much more. Competitive research, rank tracking, SEO Audits, Content Calendar, Content SEO Template, Backlink Reports, and more. SEMrush has an affiliate program.