Dr. Link Check - Broken link checker with malware and parked domain detection
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
BrokenLinkCheck - Free Broken Link Checker / Online Dead Link Checking Tool - find bad hyperlinks
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
DRKSpiderJava - DRKSpider is an open source website crawler (sitemap generator) and link checker. Features:
SEOquake - SEOquake provides a browser extension to conduct on-page SEO audit.