QuizUp - QuizUp gives you the opportunity to test your trivia skills against friends and strangers throughout the world.
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.
A Google a Day - Online trivia game where you use Google's search to answer questions as fast as you can.
Google Trends - Explore Google trending search topics with Google Trends.
Trivia Crack Kingdoms - The amazing quiz game that lets you test your knowledge and challenge your friends to see who is the smartest. Developed by Etermax
Keywords Everywhere - Free browser add-on for keyword volume, CPC & competition