I need to come up with a right angle gearbox (example)

I’m not a blacksmith and local hardware stores are coming up empty apart from selling a right angle drill attachment (which would work but they’re a bit pricey for my purpose).

The purpose: to hide a water valve (positioned upright) & control it from the other side of a wall. (back story)

My ideas so far:

1. find a broken angle grinder that someone threw away (seems unlikely) & cannabalize the gears
2. build right angle gears out of wood
3. harvest worn down bicycle cassettes from the trash and orient them at right angles against each other. They are designed to mate with a chain, so I’m not sure how well it would work. The valve is only turned on/off a couple times per year, so maybe I can get away with it.
4. go to a toy store and find a kid’s Capsela set (do they still make these?); though I imagine it might exceed the cost of a right angle drill accessory anyway and it would possibly break under stress.

What other tools or appliances should I look for on a dumpster dive which would likely contain a right angle gearbox?