This wiki page holds a list of designs publicly available. You can edit this page to include missing designs.
The first one we know of!
Better bout by strocknar
fffiddle bout attachment for shoulder rest
Easy printing Electric Violin
Easy printing Electric Violin original
Several variations here
The JAx 5 String Violin (+6 string)
Rock-Star Electric Violin V.3
DDM Electric Violin
Strativariant Rev 4
A modular, 3D printed, open source acoustic violin. Very easy to change out parts and experiment!
Functional Stroh violin
Note: They have a really good list of parts.
Claims to be concert-quality 3D printed violin