effective_dart packaged the official Effective Dart (opens in a new tab)
style guidelines as a ready-to-use analyzer configuration. Instead of hand-picking dozens of lint rules, projects could add a single dev dependency and follow the canonical Dart style.
Legacy
The package served the community until the Dart team shipped the official lints package, which now fills the same role.
effective_dart is retired, but it remains a project I'm proud of — it helped thousands of projects write more consistent Dart while the official tooling caught up.