An add-on: They're called contour plugs and used instead of Euro plugs on appliances that draw more than 2.5A. They came up along with the first Schuko receptacles in the 1950ies. Many old radios and tape recorders have them. Euro plugs came much later.
I haven't seen anything but photo lamps with a fused plug. My old 1000W Super 8 movie light has that too.
The ungrounded plugs I was referring to are completely round and have small pins, just like Europlugs, but unsleeved.
Plus the pins were partially split in halves, so if the plug lost contact you just bent them apart and that was it.
