I used to have this tube & latex sleeve combination, with a hand pumped bulb attached to it via a short length of tubing. It was not a penis pump, and it was nowhere near as elaborate as anything available today if you Google 'sleeve masturbator with hand pump'!
It allowed for almost hands-free masturbation so it would at least feel a little bit like you weren't doing it yourself. Squeezing the hand bulb caused the sleeve to move up and down on your erect penis.
The only other strange thing I tried once, was a shop vac. The hose was wide enough to accommodate my girth, unlike a common household vacuum. I had to be careful to not allow for a complete vacuum seal, as it would start to be more painful than pleasurable. This was a one-time thing as the sensation wasn't worth repeating.
Something that I did use quite often was condoms. Condoms for masturbation? Yes. A little lube inside before putting it on gave a great sensation as it move along my shaft. Plus I really like the idea that I could masturbate anywhere I wanted in my place without having to clean up the cum after I came.