@3dp from printables has created stackable PCB stands with three step sizes, namely 1 mm, 2 mm, and 3 mm. The diameter of the "nails" ranges from M2 to M14

Brackets of the same height can be stacked, so they can be easily organized and stored. That is, brackets of 2mm size can be stacked with other 2mm size brackets, and brackets of 3mm size can be stacked with 3mm size brackets.

The model is from https://mp.weixin.qq.com/s/59OcY7frCnFX_XqI58QRpghttps://pan.baidu.com/s/183IGdEEj6rbTYptMw0zGCA?pwd=t7n4