This is a stackable rack or tray for the Raspberry Pi. I've tested it with a Raspberry Pi 3, but will work for any Raspberry Pi with identical mounting hole locations.

This should be simple to print as it doesn't require any support or raft. Just print, mount your Raspberry Pi and stack. There is a connector included to keep stacks next to each other together.

Let me know if you have any trouble and I'll see if I can help.