Beta Family - 50,000 testers to test your app
TestFlight - iOS beta testing on the fly.
Erli Bird - For developers & testers alik
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.
TestingCatalog - TestingCatalog is a community of beta testers and developers exploring android apps and exchanging feedback.
TestFairy - Painless Beta Testing