TestFlight - iOS beta testing on the fly.
Boombox.io - iOS devs rejoice! Embeddable HTML and hosted TestFlight beta sign-up forms.
TestFairy - Painless Beta Testing
Visual Studio App Center - Continuous everything – build, test, deploy, engage, repeat
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.
Beta Family - 50,000 testers to test your app