MINEute and hour hands for standard clock movements. I had no luck printing second hands, that post is too small.

This thing was made with Tinkercad. Edit it online https://www.tinkercad.com/things/id5tdNgvL5N

Use a low layer height, 100% infill. You need this to be thin and light, but also reasonably sturdy. (At default height of 1.25mm, 3 layers at .30mm works well.) It will work at 1.6mm if you want thicker arms.