SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Lumar - (Previously DeepCrawl) Hosted SEO spider to analyze and find problems with websites.
Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!
Website Checker Tech - WebsiteChecker.Tech is SaaS tool that detects SEO and availability issues of your website, making it easier for you to fix them.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
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.