Here is my version of the extension cord support that fits better for my needs. I install these usually underneath my desk and its annoying that all the cables usually just falls down from there. In this version you can add velcro strips or zip ties to hold the cables and make it look more organized. I do not usually print with white filament but with that it is easier to see how it looks. Now there is only 2 cables but you can maybe imagine how horrible it will look be soon...

Middle part is not supporting that much the extension cord itself but it is more for the support for the cables. Printed with generic PETG as that was only white filament what I have at the moment. PLA should be OK too as there is not that much load on it.