Are there any uses for a 120x240 12x24 transformer? I might be getting one soon but I can't think of any uses for it.

Can you be a bit more specific..? I'm assuming you mean 120/240V in, 12/24V out..?

Powering low voltage incandescent lamps is a use that springs to mind, what is the current rating..?

I don't know the current rating, but I think it's 12/24v out.

I don't know the current rating, but I think it's 12/24v out.

If it's a reasonable size, you could use it for low voltage lamps, or maybe build a battery charger or something. Always uses for stuff like this

I got the transformer today, it can handle a whopping 40 amps at 12 volts, or .5 KVA.

With some SCR stabilizing rectifier, with its 40A it could work as an auxiliary starting aid for car in winter, I think it could be able to deliver at least 100A for the few seconds...

you can also Buck a transformer to drop line voltsge down. to make incandescent lamps to last a bit longer
if like voltage is 122 volt. you can buck it to drop 110 volt
or 12 volt boost on top of 120 volt and imagine running
130 volt incandescent at full power.