Netpeak Spider - A desktop tool for fast and comprehensive technical audit of the entire website.
Ahrefs Backlink Checker - With the world's biggest index of live backlinks (over 15 trillion), Ahrefs Backlink Checker will show you the most complete backlink profile for any website.
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.
SEO Crawler - A web-based crawler with real-time crawl feedback.
Google SERP Snippet Optimization - SEOmofo tool replicates the appearance of a snippet in Google SERPs, which allows SEOs to optimize a page title and description for maximum click-through rate.
ContentKing - The world's only Real-time SEO Auditing and Content Change Tracking suite.