The popular Flutter toolkit relies on the Dart language, so developers writing Flutter apps—for Android, iOS, or other targets—use Dart. To find a list of Flutter apps, visit the Flutter showcase.
Google engineers use Dart to create many apps, including some that are essential to Google’s business. For example, if you use the Google Ads web or mobile app, you’re using a Dart app that supports much of Google’s revenue. Also, the Assistant team at Google uses Dart for features in Smart Displays, as described in this announcement.