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.
Screaming Frog - Screaming Frog is search engine marketing agency offering search engine optimisation and pay-per-click advertising services.
SECockpit - SECockpit is a keyword research and SEO management tool.
SEMRush - All-in-one Marketing Toolkit for digital marketing professionals.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
SEOmator - SEO website analysis & audit tool