Five usability- and design sites I use:
1. Discount software-design method:
https://fivesketches.com/quality-software-designs-by-sketching/
2. UK's methods and patterns:
https://design-system.service.gov.uk/
3. Nielsen Norman Group's posts about user research and design:
https://www.nngroup.com/articles/
4. MeasuringU's posts about research statistics:
https://measuringu.com/
5. USA's definitions and resources:
https://digital.gov/resources