Fuzix (a Unix like OS for 8 bit computers) has lately become popular due to that Fuzix now supports the Raspberry Pi Pico $4 microcontroller.
I searched for Fuzix implementations for Commodore 64, but there is none, but Commodore is mentioned here:
https://github.com/EtchedPixels/FUZIX/issues?q=is%3Aissue+commodore
Fuzix exists for some 6502 based system, but the Fuzix developers thought the floppy disk drives for Commodore were too slow, but Commander's SD card might be fast enough. Also commander has 2 MB RAM maximum, but C64 could have 2 MB RAM using REU.
It might be interesting for someone to port Fuzix to Commander X16.
I found some video demonstrating Fuzix on a ZX Spectrum: