CryptoKitties - Breed and collect adorable creatures using Ethereum
Tango Card - Tango Card bundles an awesome catalog of e-gift cards and other e-rewards with easy-to-use technology and expert program support.
Mars Genesis - 10,000 unique parcels of Mars stored on the blockchain
Tremendous - Tremendous is a customer and employee loyalty platform that allows companies to reward their customers for surveys promotions and referrals.
Crypto Corgis - Crypto corgis live (and die) on the blockchain
Rybbon - Send digital e-gift cards as marketing incentives or rewards with Rybbon, which integrates with Marketo, HubSpot, SurveyMonkey, and Qualtrics.