Sensor Tower - Sensor Tower is a platform for app store optimization and app industry intelligence.
Viable Fit - Measure and improve your product market fit
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.
Product Fit - Measure product/market fit in app with your users.
appfigures - Cross-platform app store analytics for all of your mobile apps.
Product/Market Fit Survey - Check how close your product is to Product/Market fit