Mangirdas Kazlauskas started last year a series of articles about design patterns in Flutter. Each article describes a design pattern, as described in the literature, and also provides the implementation in Dart. I discovered this series only recently, and I jumped into it immediately.
You can also download the app code used in the articles.
Dart Data Class Generator for Visual Studio Code
Not exactly recent, this extension allows you to generate Dart data classes easily, fast, avoiding boilerplate and external code generation. You can also automatically generate code for
Equatable. This extension is already one of my favorites.
Vandad Nahavandipoor is going fast with his tips and tricks for Flutter (and Dart). Every day he publishes one (or more, often more), code snippets with some small features of Flutter or Dart that you might not know about. Recently, I found interesting the Capturing Stack Traces in Dart Exceptions and the Calling Optional Functions in Dart. You should definitely subscribe to the repository feed.
I have experimented with the Adobe XD plugin that generates Flutter code directly from your design. I must say that I was not that impressed with the result. But someone who is mainly a UI designer, and not a developer, might find it much more useful. The plugin is now updated for Flutter 2.
I like simple articles. Not all developers know the basics about all the aspects of Flutter. One of them is how to handle different themes in your app. There are plenty of articles around about that, but I read this from Ali Rıza Reisoğlu very easy to understand.