I tried this as lubricant on Alps switches in my video covering a range of Alps lubes.

Graphite powder is HIGHLY conductive, not a good idea in electronics or a switch.
Tungsten Disulfide is not as conductive (deemed semi-conductive), but again not great.

Being powders, both of these can migrate, especially in something like a switch where the air gets swished around quite a bit due to massive changes in volume. While by themselves they would be unlikely to cause a switch to short, they can get trapped in the existing lube and create conductive bridges. I wouldn't use either on a keyboard.

Tungsten Carbide is rather low risk except during manufacturing while Graphite is extremely bad for your lungs and can even enter through skin or eye contact.



Side note, stop over thinking lube.
We are not high rpm, high friction, high heat, these are keyboards not a mission to Mars or top fuel dragster. Other than drag due to viscosity you aren't going to notice a difference between the most expensive lube and the cheapest lube. Just make sure it's safe on plastics and bare in mind viscosity, thicker feels smooth, thinner feels more crisp. Viscosity is more important than the type of lube you use and not all switches get better with (more) lube. If they already have a good amount of lube and your springs don't ping more lube will do little to nothing.