From my old class converter plugin, Reclass.
Style: clean, minimal, flat
Program used: Studio
There are two toolbar buttons; Convert opens the class converter, and Automatic takes the top suggestion and auto-converts everything selected to that class. I designed their icons on a 16x16 grid, and exported them at 32x32 pixels so they appear crisp and smooth both in the Plugins tab and in the Quick Access Bar.
The Convert dialog has barely any lines or distractions, it’s very clean:
That small icon opposite the top suggestion tells you it’s the class type that the Automatic button would choose, hence why it shares the same image as the Automatic button.
Some more states, including empty states which have their own uniquely designed icons:
Find a class
Multiple instances with different class types selected
Instance(s) selected with no suggested classes
I think I did a fairly good job with this plugin’s UI design - what do you think?