Looks like I can’t count; here are a few more free tools I love using for SEO:
BuiltWith is a lightweight, user-friendly Chrome plugin that will tell what technology a site uses (like cms, server, hosting, analytics, and more).
CopyScape let’s you enter a URL and learn if there is duplicate content elsewhere on the web.
Feedthebot has some tools worth checking out.
Firebug is a Firefox extension for web dev and technical SEO to help you inspect elements of code, code mockups live into the browser, and more.
Google Alerts and Talkwalker help you monitor the web for new mentions of your brand or highly desired keywords.
SEMrush shows data on paid and organic traffic and keywords. It is accessible through the SEObook and SEOQuake Toolbars.
sg.SerpStat.com is a keyword generator similar to Uber Suggest and keywordtool.io. It is not as thorough as those but is wicked fast and does a nifty job segmenting keywords into groups.
SpyFu, like ,SEMrush, shows some data on paid and organic keywords and traffic.