Product Hunt - A website that lets users share and discover new products
TestFlight - iOS beta testing on the fly.
Betatesters.io - The platform connecting mobile developers and beta testers
TestFairy - Painless Beta Testing
BetaList - BetaList provides an overview of upcoming internet startups. Discover and get early access to the future.
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.