uxtoast: Learn UX Design - Become familiar with design laws and learn how to use them.
ASO Tools by AppFollow - Tools for App Store Optimization in App Store & Google Play
UX Design Trends 2016 - A 164-page free guide
App Launch Checklist - Planning tool for launching your app successfully
UXDesigner.top - Best UX Designers every week
StorePreviewer - See how your app will look like on the App Store