BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
sitebot.ai - The easiest way to monitor that your website is working as it should. Sitebot uses a real browser to test your site and login automatically.
Dead Link Checker - Check for broken links on any website
DiffHub - Automated Web UI & Functional Testing for non Engineers
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Ghost Inspector - Easily create automated browser tests for your websites and web apps. Ensure everything works and looks the way it should. No coding required. 14 day free trial!