Research-based UX guidance, including a ton of helpful articles about the design process, research methods, and user testing. Mostly focused on the user research side of things, not much regarding UI Design Principles.
An article platform with stories on user experience, visual design, product design, and more. Articles on Medium are written by a large variety of writers and cover a range of topics. Normally, the content isn’t very systematic. Treat the platform more as a good-to-know type of information source.
Interaction Design Foundation
A library of open-source UX design resources, including new articles published every day. There are also local
meet-ups (virtual and in-person) that are free to attend and open to everyone. A much more systematic information store.
List of Design Systems