Cydia - An alternative app store for jailbroken devices.

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

Zestia - Zestia is a mobile app designed to assist you in organizing your hectic schedule, social life, and professional persona.

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.

Fnd - Browse Apple App Store and iTunes on the Web

appfigures - Cross-platform app store analytics for all of your mobile apps.