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.
KWFinder - KWFinder is a keyword research and analysis tool bringing hundreds of long tail keywords with low SEO difficulty. Try KWFinder for free!
SECockpit - SECockpit is a keyword research and SEO management tool.
Keyword Discovery - Keyword Discovery is a keyword research and analysis tool.
Serpstat - Search analytics, Rank tracking, Backlink analysis and Site Audit tool.
Keyword Revealer - Keyword Revealer is akeyword intelligence tool enabling marketers to find low competition keywords.