A small clamp you can attach to the bed of the ender 3, so you can clip a small camera. This lets you create 3d print timelapses where the part does not move relative to the camera, making the video much smoother.

If you like, you can print this with no need for M3 parts, just a finger screw to tighten the connection between the plate and the camera clip. I haven't had any problems with this yet, but you might experience softening of the parts, as they are attached to the hot print bed.