Step On This - Samigon And Fujifilm
The 35mm cameras were easy - nearly all the better consumer types had mechanical self timers built into the bodies. You flicked a switch or wound a lever, pressed the shutter button, and ran around to the front of the lens and looked distinguished and elegant. In 10 seconds.
It was a bit harder to do with the studio monorail camera or the wooden field camera because the commercial shutters on the lenses had no "V" setting. ( V was the universal code letter for self-timer. Don't ask...). The best solution was one of the air releases similar to the one in the heading image. You attached it to the cable release socket, paid it out over the studio floor to the selected position, commenced looking distinguished and elegant, then stomped on it.
The air bulb shot pressure through the line to the piston and it pushed a rod down into the cable release socket. With a bit of luck you only had to look good for one second - not 10.
You can still do the same thing with cameras like the Fujifilm X-E2 and X-100t - they feature a good old fashioned cable release socket as well as electronic sockets at the side for switched releases. Selfie heaven.
Actually, if you think about it, I'll bet there would be a market for an electrical switched release that you could put on the floor for stomping...but until then, the Samigon Stomper is here.