I designed some icons using the Autodesk Icon Guidelines to create some Cube and Box icons based on the guidelines, each icon has a light and dark theme for each color and shape.
Here is an example of each icon inside Revit 2024, all the images are available in Autodesk.Icon.Example.
Update icons
In the video below I created the project RevitAddin.Icon.Example to swap the icon depending of the theme in Revit, the code is designed to work with Revit 2024+ using the event ThemeChanged.
Also, update the project to work with NET Core using the preview version that runs in NET 7.0.