Handspinner

I didn't want to play with anyone's design, so I made my own!
It has an ergonomic thumb/finger holder!
Use 608 bearings (shielded or not, doesn't matter).
Bearings should fit snugly just by pressing with your hand, and if you are lucky to have a vice, then it should be fine.
If you have issues with bearings not fitting or being too loose, print at a different scale.
Hope you like it!