Zendesk - Zendesk is a beautiful, lightweight help-desk solution.

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

Freshdesk - Freshdesk is a cloud-based customer support software that lets you support customers through traditional channels like phone and email, social channels like Facebook and Twitter, and your own branded community

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.

HelpScout - Help Scout is a simple, straightforward way to provide excellent support

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