SERPStream is a 100% free SEO tool. Members can keep track of their site's Search Engine Results Page position with updates as frequent as a dozen times a day. SERPStream have a great newsletter, sends email alerts, and have a state of the art keyword rank tracking dashboard.
MetaTagTool.com - Meta Tag & Open Graph Tag Generator, Simulator, & Analyzer
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
Moz Link Explorer - Search engine for links Perform competitive website research.
SEO PowerSuite - Get all SEO tools in one pack - download free edition of SEO PowerSuite and get top 10 rankings for your site on Google and other search engines!
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
OpenGraph.xyz - Check how search engines and social medias such as Google, Facebook, Twitter display your website