Screaming Frog SEO Spider - The Screaming Frog SEO Spider is a small desktop program (PC or Mac) which crawls websites’ links...
LinkChecker - LinkChecker is a free, GPL licensed website validator.
Sitechecker - All-in-one SEO platform including rank tracker, website SEO audit tool and website changes monitoring. Detailed reports by 100+ parameters with how-to-fix guides.
DRKSpiderJava - DRKSpider is an open source website crawler (sitemap generator) and link checker. Features:
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
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.