A small clamp that will hold even a thick music book on a music stand.

Print it with support. Any material is suitable.

I use the spring from a 2-inch spring clamp. E.g., https://www.amazon.de/Federklemmen-Hochleistungs-Einhandzwinge-Holzbearbeitung-Fotohintergrund/dp/B09KTNHDXX

Shorten both spring ends by about 10 mm and bend them at a right angle by 3 mm.

Put the spring in place, press the clamp parts together, and insert a small screwdriver. From the opposite side, screw in a 20 x 3 mm screw and fix it with a nut.

For an even bigger bracket see my https://www.printables.com/model/1271412-music-bracket-with-huge-opening