Personally, I use these tools when checking the accessibility compliance of the web apps I build:
This elm based prototype helps designers build color palettes that conform to accessibility standards. Check out the project's website here.
- (Some people won't agree, but) W3
Specifically ones that work on web accessibility at work everyday. Shout out to VWC and all the troops that help me be a better developer everyday.
Drop links and personal experiences below.