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.
AppLaunchpad - Create free beautiful screenshots for App store/Google play
Sensor Tower - Sensor Tower is a platform for app store optimization and app industry intelligence.
iOS Jetpack - Beautiful easy-to-use screenshot templates for App Store
AppStor.io - Free useful tools and services for App Store developers / marketing managers and owners.
Smartmockups - Create stunning product mockups, easily and online.