Nifty - Manage projects, work, and communications in one place.
The Product Management guide - A book on how to create and ship products that people love
Intercom on Product Management - The ultimate resource for aspiring product managers
Xobin - Most Comprehesive Pre-Employment skills testing and Psychometric Assessment Platform.
GitHub Project Management - No-fluff guide to building a collaborative development team
Software Product Management Stack - Resources & tools to help you manage your software product