completely free for everyone. Its build-in Flutter Dart
...The layouts are responsive and customizable, helping developers save time when prototyping or launching apps. The project is structured modularly so developers can pick and choose specific screens or flows instead of using the entire template. It’s one of the most comprehensive UI repositories for Flutter, serving both as a design inspiration library and a starting point for actual app development.
Rainbow Brackets for IntelliJ based IDEs/Android Studio/HUAWEI DevEco
...Create and merge PRs and perform code reviews from inside your IDE while using jump-to-definition, your keybindings, and other IDE favorites. If you didn't like the built-in colors, or want some new color but don't want to try out and pick colors. Please use color generator. And you can use the color generator and config your number of colors at the same time.