Ahrefs Backlink Checker - With the world's biggest index of live backlinks (over 15 trillion), Ahrefs Backlink Checker will show you the most complete backlink profile for any website.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
PrePostSEO Domain Authority Checker - DA PA Checker (Domain Authority Checker) is developed to check bulk DA PA with spam score & IP Address for up to 500 URLs at once.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
Semrush Authority Score Explained - Find out how Semrush Authority Score may help you to get better at your link building efforts when looking for quality domains, and improving your own website‘s authority.
Dead Link Checker - Check for broken links on any website