Dr. Link Check - Broken link checker with malware and parked domain detection
Screaming Frog - Screaming Frog is search engine marketing agency offering search engine optimisation and pay-per-click advertising services.
BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
SEOmator - SEO website analysis & audit tool