@Lightlyseared Wait, it what context? Sorry, as a lab worker who uses liquid nitrogen I’ve never heard of it being very hazardous at all before, so I’m wondering how i missed it. Without being stupid, it’s pretty hard to hurt yourself with it in any way I’ve used it.
Also, are we talking about the storage and transport, or direct use? Because they’re a little different. Liquid nitrogen can be very dangerous when transporting, but no more so then any liquified gas, it’s just used a lot more, and so has more casualties as a result. The actual direct use is quite safe as long as you don’t, say, drink it or hold your hand in it for an extended period.
As for leidenfrost, all you really need is a temperature differential. Liquid nitrogen and pretty much anything will work, or likewise a very hot surface and something more mundane like water as @cazzie said.
As far as cold liquids, there’s not a lot that will work all that well. Other gasses are hard to acquire, more dangerous, and probably much more expensive. Why do you need something else? Just another example? If it’s just one, the water and hotplate would probably work fine. And then you can show that a surface at a lower temp, below the Leidenfrost point, will evaporate faster. You can’t really show that with liquid nitrogen since the leidenfrost point is still quite cold.