My favorite freestanding desktop keyboard is still the original Macintosh Extended Keyboard[1] (the 2 is ok, but not as good as the original). I still have one in use on my linux machine. It requires a ADB to USB converter, but it's HID and so it works with anything. That keyboard is from the 1990 timeframe, so it's about 25 years old now and still works wonderfully.

[1] https://en.wikipedia.org/wiki/Apple_Extended_Keyboard