The Product Management guide - A book on how to create and ship products that people love
TestRail - TestRail provides comprehensive test case management for software testing. Organize your testing, boost productivity, get real-time insights, and track progress toward milestones. Integrates with leading issue tracking and test automation tools.
Product School - The global leader in product management training
TestLink - Test & requirements management
Product Management Exercises - A repository of product manager job interview exercises
Qase - Test case management software for QA and development teams that helps you make your product better.