UserTesting.com - Usability testing has never been easier. Get videos of real people speaking their thoughts as they use websites, mobile apps, prototypes and more!
Really Good UX - A library of screenshots for UX inspiration
Instabug - The top apps in the world rely on Instabug for beta testing, user engagement and crash reporting.
Startup Timelines - How the frontpages of famous startups changed over time
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
UXTesting - Discover how your mobile users feel