Apple App Analytics - Apple's very own iTunes Connect App Analytics
AppGrowthLab (by SplitMetrics) - 55 app growth lessons from 30 app marketing experts
Adapty - Low-code price personalization for in-app subscriptions
The Creative Marketer - Techniques & tools for copywriters, marketers, and creatives
Qonversion - The subscription data platform for mobile-first companies
RevenueCat - In-app subscriptions made easy