I made these hooks to store my drawing tablet and pen when I'm not using it. The pen holder also doubles as a headphone hook. Works like a charm. You could make it larger and put a laptop on it, but I don't really feel comfortable hanging my laptop off the side of a desk.

Drawing tablet and pen model is Veikk A15.

Magnet size is about 6.8 mm in diameter and 1.8 mm in height.