Viable Fit - Measure and improve your product market fit
Software Product Management Stack - Resources & tools to help you manage your software product
OpinionX - Stack rank people's priorities in minutes with OpinionX's free ranking surveys.
The Product Management guide - A book on how to create and ship products that people love
Product Fit - Measure product/market fit in app with your users.
Product Management Exercises - A repository of product manager job interview exercises