My favorite 3d printed object s are the adapters, small incredibly useful objects that lets us use stuff we alrteady have in new and improved ways. And on Carlo’s bike now is fully fitted with 3d printed stuff 
Tail light (ABS on CB printer)
Adapter for a powerful torch as a front light (Nylon on CB pinter)
And a place to carry the bluetooth speaker (!) (Nylon on CB pinter)
