Plateless keyboards with PCB-mounted MX-compatible switches.
Keyboards with plate-mounted MX-compatible switches and special cutouts in the plate. Those are only custom.
Keyboards with sockets for switch swapping on the PCB (and a special plate, presumably).
Keyboards with Alps SKCM/SKCL switches or respective clones.
So, _almost_ any Cherry G80, some vintage keyboards like Chicony KB-5191, Uniqey keyboards, the few hot-swap keyboards and some customs. Also, pretty much anything with complicated/simplified Alps or clones like Matias switches.