Waitlist API - Quick and easy waitlist with built in referral.
Orcaso - Work is now gamified. Achieve greatness through orcaso.io, the simplest project management/team collaboration tool.
LaunchList - Create waitlist with referral for your product launch
GetBadges - GetBadges is a gamification platform which allows developers to play and compete while using software development tools.
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.
Habitica - Habitica is a free habit building and productivity application.