Design Systems Handbook by DesignBetter.Co - Your guide to design systems best practices
Design Principles - An open source repository of design principles and methods
The DesignOps Handbook by InVision - Guide to understanding how DesignOps help design teams scale
The modern web design process - An in-depth guide to the processes behind great websites.
Atlassian Design - Design, develop, and deliver
InVision Studio - The world’s most powerful screen design tool