Funnily enough I found a couple of (unused) flashbulbs several months back. I wonder where I put them. There was also a test bulb in one of my "old stuff" boxes. It had an ordinary low voltage electric bulb with dark green plastic cover. You could use it to make sure the flashgun was working.
p.s. the flashbulbs were the blue coated daylight type.
I get away with displaying the flashbulbs because I have been given one of the rooms that was meant to be a bedroom, but is unneeded since there are only two of us. I use it as my 'museum' of photographica.