I have found a 3D printer to be invaluable in enabling me to get Arduino projects completed. The attached photos show two different plastic frames/supports for controller that goes into a 3-gang wall box and a mega with two daughter boards for running house utilities.
Prior to stacking the boards as shown in the photos, the wiring bundles were total nightmares.
(system did not upload the photos, said they failed the "security check." What?)