I don't see a barcode scanner in the icon library and it seems like an oversight that would be easily corrected.
The "Insert -> Media" choice for Barcode Scanner has it's own icon. When you add one, it makes a button for opening the scanner, but it seems like Power Apps should offer an Icon to put in your app as well, like for a link to the screen where my scanner button is.
Where can I request this that it will hopefully get some visibility?