Unlikely, at least in the sense being discussed here. A Hall effect sensor works by running a constant current in one direction while measuring the potential d

Unlikely, at least in the sense being discussed here. A Hall effect sensor works by running a constant current in one direction while measuring the potential difference in a different axis. The keyboard’s PCB needs to be able to register a range of values, not simply binary on-off. Regular keyboards aren’t equipped to do that. Typically in an HE keyboard, the sensors are mounted to the PCB. The “switch” itself is just a neodymium magnet at the end of a POM stem, in a polycarbonate housing with a spring. There are other kinds of magnetic switch that have historically been used in keyboards – e.g. Fujitsu used reed switches in the 70s – and in theory you could probably build them into a Cherry MX-compatible package. But they wouldn’t provide many of the benefits of HE keyboards, besides smoothness and reliability, and I’m not aware of anyone doing it.