The Stanford Online Accessibility Program provides resources for Stanford web designers, developers and content creators so that they can produce materials which are accessible to the broadest audience possible. The program achieves this through the promotion of universal design and web standards compliance.
For developers, Rob Dodson from Google has an easy-to-follow presentation on the foundations of accessibility and some practical tips: Focus and Semantics
Accessibility is My Favorite Part of the Platform, Rob Dodson, Google I/O 2016
Good accessibility = Good UX.