Ahrefs - Ahrefs is a toolset for SEO and marketing. We have tools for backlink research, organic traffic research, keyword research, content marketing & more. Give Ahrefs a try!
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.
Moz - Backed by industry-leading data and the largest community of SEOs on the planet, Moz builds tools that make inbound marketing easy.
Google Trends - Explore Google trending search topics with Google Trends.
SE Ranking - All-in-One cloud-based SEO software for agencies, marketing teams and webmasters
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition