(Something I cooked up out of curiosity on 2019-05-20...)
You want a list of OUIs?
Have a list of (Ethernet) OUIs (on Linux): ip l | grep link/ether | tr -s ' ' '\t' | cut -f 3 | cut -d: -f 1-3
or ifconfig | grep HWaddr | tr -s ' ' | cut -d ' ' -f 5 | cut -d: -f 1-3
Here’s macOS: ifconfig | grep ether | tr ' ' '\t' | cut -f 3 | cut -d: -f 1-3