Sensor Tower - Sensor Tower is a platform for app store optimization and app industry intelligence.
Survey Monkey - Create and publish online surveys in minutes, and view results graphically and in real time. SurveyMonkey provides free online questionnaire and survey software.
App Annie - App Annie is a marketing analytics tool available for apps of all kinds. With App Annie, you can track sales, traffic, and a variety of other factors pertinent to monitoring an app's trajectory.
Pollfish - Pollfish's mobile survey platform provides today's professionals with deep insights from real consumers leading to better business decisions. Create your first survey in minutes.
appfigures - Cross-platform app store analytics for all of your mobile apps.
Crunchbase - Crunchbase is a platform for discovering industry trends, investments, and news about companies around the world.