As starters, there may be good interest in clear turn signals (for use with the bright-colored LEDs), air dams or air vents for the front cowling, mirror streamlining "bullets," foot shields, connector weatherproofing, and mounting plates/adapters for various gadgets. The list is endless, really.
Anybody wanting these items could download the 3D printer files for them, and either 3D print them (DIY) or have them made by commercial 3D printer shops. My local library (remember libraries?) has 3D printers, and held classes to teach people how to make things with them.
Maybe "the future" can start right here.

.