This checklist uses The Web Content Accessibility Guidelines (WCAG) as a reference point. The WCAG is a shared standard for web content accessibility for individuals, organizations, and governments.
Lighthouse is an open-source, automated tool for improving the quality of web pages. You can run it against any web page, public or requiring authentication. It has audits for performance, accessibility, progressive web apps, SEO and more.
Skew makes adjusting layers in bulks extremely easy by letting you directly touch layers in its own dedicated timeline.