Link Research Tools - Recover, Protect, Learn and Grow your SEO with LRT.
KeywordTool.io - KeywordTool.io is the best FREE alternative to Google Keyword Planner and Ubersuggest. It uses Google's autocomplete feature to get over 750+ long-tail keywords for any given query.
MegaIndex - Use MegaIndex to identify your inbound link profile and boost your linkbuilding strategy. View social activity, research backlinks, identify competitors, and analyze anchor text.
Google Trends - Explore Google trending search topics with Google Trends.
Ryte - Ryte is a web-based software invented for technical optimization for search engines and improvement of websites.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition