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.

Cydia - An alternative app store for jailbroken devices.

Sensor Tower - Sensor Tower is a platform for app store optimization and app industry intelligence.

AppRecs - AppRecs sorts through reviews in the App Store and automatically helps you filter out inauthentic results.

AppStor.io - Free useful tools and services for App Store developers / marketing managers and owners.

Fnd - Browse Apple App Store and iTunes on the Web