Fyne - The Fyne toolkit is an easy to learn, free and open source, platform for building graphical applications for desktop, mobile and beyond.
Adapty - Low-code price personalization for in-app subscriptions
Gio UI - Gio is an open source library for creating portable, immediate mode GUI programs for Android, iOS, Linux, Windows, macOS.
Apple App Analytics - Apple's very own iTunes Connect App Analytics
AppGrowthLab (by SplitMetrics) - 55 app growth lessons from 30 app marketing experts
CleverTap - CleverTap offers blazing fast analytics, powerful real-time segmentation, multi-channel messaging, A/B testing and personalization in one unified solution.