CleverTap - CleverTap offers blazing fast analytics, powerful real-time segmentation, multi-channel messaging, A/B testing and personalization in one unified solution.
Zeplin - Collaboration app for UI designers & frontend developers
Apple App Analytics - Apple's very own iTunes Connect App Analytics
Mightytext - Send & Receive SMS Text Messages from your computer. Sync'd with your Android #
Callcounter.eu - Callcounter gathers API usage data and gives you insight in trends, slow parts and errors.
ActiveWords - Auto correct on steroids