SEO Analyzer By Neil Patel - A free SEO analyzer for your site
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.
Serpstat Website SEO Checker - Check your website's SEO, analyze competitors and keywords
Backlink Tool - A backlink tool to index your links quickly and freely.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
SEMScoop - Find and analyze easy to rank long-tail keywords with free SEMScoop Keyword Difficulty Tool, Start using them for SEO, PPC, content creation and all your marketing activities