cutie mark dress is overwhelmingly used to describe the thing from the Cupcakes fanfiction and should not imply “cutie mark on clothes”, but has been tagged a few times on normal dresses, and needs cleanup.
Apparently, there’s also a cutie mark brooch tag. It only has one instance, so there might be no point in keeping it. Or maybe Principal Celestia’s accessory also could qualify as a brooch, thus justifying the tag? I’m honestly not sure.