We love these style guides:
18F Content Guide
Buzzfeed Style Guide
A List Apart Style Guide
If you’re working on your own style guide, these resources were helpful to us:
Accessibility Cheatsheet
18F Accessibility Guide
Designing for Screen Reader Compatibility
Accessible Color Combinations
WAVE Web Accessibility Evaluation Tool
The Conscious Style Guide
GLAAD Media Reference Guide
Want to adapt our guide to use at your own organization?