productboard - Beautiful and powerful product management.
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.
ProdPad - ProdPad helps your team gather ideas, surface the best ones and turn them into product specs, and then put it all on a product roadmap.
Google Trends - Explore Google trending search topics with Google Trends.
ProductPlan - Cloud-based product roadmap software solution
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition