LinkChecker - LinkChecker is a free, GPL licensed website validator.
SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
DRKSpiderJava - DRKSpider is an open source website crawler (sitemap generator) and link checker. Features:
DeskAlerts - Send alerts to any corporate device: PCs, phones, tablets, etc.
Dead Link Checker - Check for broken links on any website
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.