Viable Fit - Measure and improve your product market fit
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.
Product Fit - Measure product/market fit in app with your users.
Google Trends - Explore Google trending search topics with Google Trends.
OpinionX - Stack rank people's priorities in minutes with OpinionX's free ranking surveys.
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition