Betafy - Where startups meet beta users!
Product Hunt - A website that lets users share and discover new products
AlternativeTo - AlternativeTo lets you find apps and software for Windows, Mac, Linux, iPhone, iPad, Android, Android Tablets, Web Apps, Online, Windows Tablets and more by recommending alternatives to apps you already know.
lucr - Get early adopters for your startup
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.
Betatesters.io - The platform connecting mobile developers and beta testers