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.
Keyword Discovery - Keyword Discovery is a keyword research and analysis tool.
Keyworddit - Keyworddit is a popular platform that can help you to raise your SEO game in a smooth and convenient way.
SheerSEO - SheerSEO helps you to track Google Search Engine Rankings for critical keywords. PageRank, Back Links and more.
Keyword Lookup - Keyword Lookup is an innovative chrome extension that can provide you monthly Search Volume of keywords.
iSpionage - AdWords competitor keywords with the click of a button and monitor competitor PPC landing pages.