These inexpensive HP t610 thin-client computers are great for re-purposing in low-power applications, but I kept accidentally knocking mine over when it was stored vertically, and felt that brackets of some kind were needed (mine arrived with only one half of a VESA mount system).

These brackets add stability without increasing its footprint very much, and the locking pins prevent them from sliding around, or dropping off when the device is moved around. They also maintain a bit of space underneath the device, where the factory case does have cooling vents.