The Sketch Design Tool
Design effectively in Sketch with the Sketch design tool handbook
Build an iOS and Android app from scratch – React Native
React Native is a popular Javascript framework that builds on top of React by using native components to create a real mobile app indistinguishable from one made using Xcode or Android Studio. The main difference with native development is that you get to use CSS, hot-reload, Javascript and other familiar techniques that the Web grown over the past decades. Most importantly, you’re building for both iOS and Android using the same codebase.
Build a cross platform app for iOS and Android – Flutter
Flutter transforms the app development process. Build, test, and deploy beautiful mobile, web, desktop, and embedded apps from a single codebase.