Someone asked a few days ago about changing individual folder colors .... I just happened to run across this website .....
It appears you have to have Nautilus installed to make it work ...... I also found one for Nemo but when I tried to run it in the terminal it told me the file could not be found .....
I was kinda interested in the one for Nemo myself .....
All that does is change the icon to a chosen one from the Yaru icon set - which is a function already included in Nemo, except you can choose from any icon set.
In Nemo, right flick the folder and choose Properties.
Then click on the Icon image button on the left hand side., That opens a new popup window with the prompts to change the icon - of any choosing from any location.