SystemFlow - Designer-First Framework for Webflow
Software Product Management Stack - Resources & tools to help you manage your software product
Design X Maker - Design X Maker: Unleash Limitless Designs Propel Your Growth
The Product Management guide - A book on how to create and ship products that people love
Designmodo - Timesaving tools for designers, developers and marketers. Designmodo offers website and email builders.
Product Management Exercises - A repository of product manager job interview exercises