lucr - Get early adopters for your startup
Betafy - Where startups meet beta users!
Beta Family - 50,000 testers to test your app
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.
Waitlisted - Waitlisted helps new brands and startups build an audience while they focus on building a product
Betatesters.io - The platform connecting mobile developers and beta testers