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.
Blinkist - Key insights from 6,000+ bestselling books and podcasts
Google Trends - Explore Google trending search topics with Google Trends.
Four Minute Books - Making you smarter in 4 minutes or less.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition
12min APP - Free reading app for summaries of nonfiction books.