Better Notes - Simple notes app that ties notes together with #hashtags
Intercom on Product Management - The ultimate resource for aspiring product managers
ClevNote - ClevNote is an amazing mobile application that helps you to write the daily memos on your smartphone.
Product School - The global leader in product management training
Notepad by Splend Apps - Notepad by Splend Apps is one of the best mobile apps that enables you to create a to-do list and notes.
The Product Management guide - A book on how to create and ship products that people love