Outsider's mark - Dishonored keychain
Mark of the outsider in a simple keyring form. Make sure the scale is right for you before printing, because I did not pay attention to what size I made it in.
For single-filament printers:
Use the MarkKeychain.stl and implement a filament change/pause at height function to change the color of the top part. Here's a video tutorial.
For dual-filament printers:
Import MarkLower.stl and MarkHigher.stl. Position MarkHigher on top of MarkLower and assign material to each part.