TestFlight - iOS beta testing on the fly.
Product Hunt - A website that lets users share and discover new products
TestFairy - Painless Beta Testing
Betafy - Where startups meet beta users!
TestApp.io - A platform that helps both mobile app developers and owners to easily share their apps with everyone to get feedback before reaching publicly to Google and App stores.
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.