Accessibility Insights, built by Microsoft, provides both a FastPass automated scan for quickly catching common issues and a structured Assessment mode that walks a tester step by step through the full set of manual WCAG checks a scanner cannot perform, like verifying logical tab order or meaningful reading sequence.
Its guided assessment format makes it a strong choice for teams building an internal accessibility testing practice, since it teaches testers what to check and why while they work, rather than just handing back a list of automated findings with no manual-testing structure attached.