Everything.PM - 300+ resources & tools for PMs, sorted by votes
Tribe of Mentors - Short life advice from the best in the world, by Tim Ferriss
PM Starter Pack - Practical guide on how to get started in product management
MentSpot - Find a mentor or become one for free
Product Manager Handbook - Interviews w/ product managers + weekly newsletter
Awesome Peers - Discover 900+ people who have free video call options