If you own a Stala PL3 mailbox, you can now print your own signboards. There's a blank board in STL to print, a blank and a version with editable texts in f3d for those of you using Fusion360, and a STEP file for anyone with some other compatible 3D modeler.
I printed my own with two colours, the board with a darker one and the texts with a lighter one. Or why don't you make up your own graphics to print on the board?!
The STLs are upright but print them flat.