This is a Python library that allows Raspberry Pi's to use the REV Color Sensor without a Roborio/FRC project.
pip3 install revcolorsensor
You will need to run the pigpio daemon for this library to work.
Install with:
sudo apt-get install pigpiod
You can run this after booting up the Raspberry Pi:
sudo pigpiod
or, run this once and it will do it automatically on boot each time:
sudo systemctl enable pigpiod