Waitlist API - Quick and easy waitlist with built in referral.
Domainz.io - Premium domains, for not so premium prices
LaunchList - Create waitlist with referral for your product launch
Amazon Route 53 - Amazon Route 53 is a highly available and scalable DNS web service.
Waitlisty.io - Build excitement for your product by embedding a simple form into your website. Signups will receive a referral code to share with their friends. The more codes they share, the more they climb your waitlist.
Brandpa - Domain names for startups