Bookmarked:
medium.com 
This is a brilliant reference project on the process and design behind creating accessible data visualizations.
Here are some of the key improvements that made our data and reports more accessible and easy to use:
- Consistent dashboard layouts
- Focused, simple data visualizations
- Accessible text to support the data
- Mobile responsive dashboards
- Special care to accessibility for screen readers
- Templates and guidance to streamline adoption
The team published their learnings in a public guide:
.