In the past few years, we have covered plenty of soft grippers for robots that allow them to easily handle fragile items. This 3D Printed Soft Robot Tri Gripper is also worth a look. It has an actuator, printed gear, and servo motor. As the maker explains:
The working principle is also quite simple, flexible fingers are connected to a slider with bridged “cables,” which is then driven by a servo using a rack and pinion.
As Layershift explains, this is just a proof of concept at this point. The goal is to print more complex grippers with multiple motors.
[Source]