Makers don’t just sit at home and make stuff. They are a social lot and as such love to share their inventions. Several places on the ‘net have sprung up, offering a place to publish – and find – designs, suitable for 3D-printing.
If you’ve made a gizmo/doodad, wish to share it with the world and it can be expressed in a .STL file, the below website is for you. And me, if I find the need for said doodad.
It’s absolutely wonderful. Go have a look-see. You might find something neat.