I don't no if you can request tutorials here but I do it anyways.
I would like to see tutorials on creating your own property panel components.
One introduction with a simple component like adding a questionmark button to the expression input component with a help text popup.
And on more advanced creating something like the columns component for the table extension.
And also one with the flow of an extension, which functions are executed when and what callbacks to the engine are made. If you don't want all your logic in the paint function where should you put it instead. And those kind of topics.