In my opinion, these are 3 elements important for every product manager.
Here's a full post on the topic: Universal vs. specific (product) skills. And unlocking your super powers in 3 steps
There are 2 assessments I think are great for product managers and aspiring product managers.
Here is 2 resources on PMwheel:
The second one is by Sillicon Valley Product Group and Marty Cagan, author of Inspired.
More information is available here: Coaching Tools – The Assessment
I suggest you start with intro books, and then choose books from good practices.
The Product Book - How to Become a Great Product Manager
free book: LINK
Build - An Unorthodox Guide to Making Things Worth Making
Strong Product People
Inspired - How to Create Tech Products Customers Love
Escaping the Build Trap
Continuous Discovery Habits
Scrum Product Ownership - Navigating The Forest AND The Trees
User Stories Applied - For Agile Software Development
Lean UX - Applying Lean Principles to Improve User Experience
Product Roadmaps Relaunched - How to Set Direction while Embracing Uncertainty
Hooked - How to Build Habit-Forming Products
Crossing the Chasm - Marketing and Selling High-Tech Products to Mainstream Customers
Design for How People Think
The Cold Start Problem
Design for How People Think - Using Brain Science to Build Better Products
User Story Mapping
Measure What Matters
The Guide to Wireframing - Chris, Bank
Lovability - How to Build a Business That People Love and Be Happy Doing It
Non-Obvious - How to Think Different, Curate Ideas & Predict The Future
Value Proposition Design - How to Create Products and Services Customers Want
to be added:
newsletters and blogs + paraticular blog posts