Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
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.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Google Trends - Explore Google trending search topics with Google Trends.
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!
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition