productboard - Beautiful and powerful product management.

The Product Manifesto - Product Managers face the biggest challenges of our day, which is why our community needs a common set of product principles.

Aha - Aha! is the new way to create visual product roadmaps. Web-based product management tools and roadmapping software for agile product managers.

The Product Folks - A volunteer-led community of product managers and makers

ProdPad - ProdPad helps your team gather ideas, surface the best ones and turn them into product specs, and then put it all on a product roadmap.

The Product Management guide - A book on how to create and ship products that people love