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!
Intercom on Product Management - The ultimate resource for aspiring product managers
Instabug - The top apps in the world rely on Instabug for beta testing, user engagement and crash reporting.
Product School - The global leader in product management training
Userbrain - Easy, fast, and affordable user testing for websites and prototypes.
The Product Management guide - A book on how to create and ship products that people love