Built-in tools in Dart are utilities provided by the Dart SDK that help developers write, debug, and analyze Dart code more efficiently. Here are some of the most commonly used built-in tools in Dart:

1. Dart VM

2. Dart Analyzer

3. Dart Formatter

4. Dart DevTools

5. DartDoc

6. Dart Observatory

7. Dart Test

8. Dart REPL

9. Dart Observatory

10. dart2native