Don't let 'berries touch the floor 
Don't let 'berries touch the floor
Don't let 'berries touch the floor
Don't let 'berries touch the floooor!

While working with bare Raspberry Pis it's easy to short out something on the underside or tear off a capacitor. Placing it on a piece of paper can work in a pinch, but I wanted a more permanent solution. 

Key info:

• tested with RPi 4B and 5, but afaik it should be compatible with all previous “B” models,
• requires four M2.5x6mm screws (unfortunately M3s won't fit PCB holes),
• you can put a piece of 1.75mm filament in the designated slot to distinguish between your Pis. It's not super visible, but won't come loose like a piece of tape could,
• FreeCAD source file and STEP are available. If you don't like it, feel free to remix.