Annex Cloud - Reward customers for completing traditional actions such as purchasing, as well as for taking...
ChatWhale - Gamify your customer communication and loyalty rewards
Voucherify - API-first Promotion Engine for promotions & loyalty.
Dealyze - Custom Loyalty Programs for any Store (YC)
Goody - All products under $10 including free global shipping
Gvouchers - Free service to sell gift vouchers to loyal customers