Netpeak Spider - A desktop tool for fast and comprehensive technical audit of the entire website.
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Checkbot - Checkbot will boost the SEO, speed and security of your site by checking you're following 50+ web best practices. Browser extension with free and paid plans.
Pulno - SEO Audit and Website Analysis. Pull up your SEO.
SEO Crawler - A web-based crawler with real-time crawl feedback.
Dead Link Checker - Check for broken links on any website