App dev Resources will be shared here:

Flutter

1. Flutter's official website
2. Flutter widgets docs
3. Google Fonts
4. Material Design
5. Here's a quick guide to get started with flutter
6. Here's a quick guide to get started with the Dart programming language, on which flutter apps run.
7. Debug your flutter app wirelssly. article here

Native (android & iOS)

React Native

1. React Native Developer Roadmap here
2. Another blog to read for react native developers to get started

General Resources

1. Programing Books here