https://www.boia.org/digital-accessibility-resources 

Color Contrast Accessibility Validator

This free color contrast validator will display the color contrast issues of a web page per WCAG 2.1 Guidelines. Color Contrast refers to how bright or dark colors appear against each other on screens; particularly with regard to the relative, gray-scale luminosity as perceived by the human eye. Use the Color Contrast Accessibility Validator

Website Accessibility Checklist

This in-depth checklist will assist you with the basic guidelines for complying with the website accessibility standard, the Web Content Accessibility Guidelines (WCAG) 2.0 A/AA. The criteria for successfully meeting each guideline is more easily achieved when considered during a website’s design process, but even if you did not account for accessibility measures while developing our site, you can still make changes that will increase overall usability of your digital presence and make it available to a larger audience. Get the website accessibility checklist

Definitive Checklist for Mobile Accessibility

With this checklist you can identify the areas of your iOS and Android apps that are prone to design and development flaws when it comes to mobile accessibility measures and compatibility with assistive technologies. The user experience and app output can vary widely between devices, operating systems, and the screen readers or other assistive technologies. By paying heed to these design considerations and following the mobile accessibility guidelines set by WCAG, your app opens up to a wider audience and is easier for everyone to use. Get the definitive checklist for mobile accessibility.

Ultimate Guide to Website Accessibility

In today’s world, owning and operating a website that doesn’t provide the same services to a disabled person that it provides to others, is called discrimination. Learn about website accessibility and how to prevent lawsuits in this ultimate guide to web accessibility. Get the ultimate guide to website accessibility. 

Chapter 1: Web Accessibility – What you need to know
Chapter 2: How to prevent a Web accessibility lawsuit
Chapter 3: The most common Web accessibility issues to avoid
Chapter 4: How to ensure your website is ADA compliant