Everything.PM - 300+ resources & tools for PMs, sorted by votes
Learn by AngelList - Venture Education Center by AngelList
PM Starter Pack - Practical guide on how to get started in product management
Sidewise - Source the best engineers, without understanding code.
Product Manager Handbook - Interviews w/ product managers + weekly newsletter
Marketplace Knowledge Hub - A curated collection of 300+ resources for learning about marketplace startups.