BOMComplete material list with links here: http://sonsts.de/blog/raspberry-pi-enclosure/

• Raspberry Pi rpi3b & 3b+ - Enclosure (rpi3b)This is a plain enclosure for Raspberry Pi 3B. The complete enclosure is modeled from scratch.***
• Raspberry Pi rpi3b & 3b+ - 2.5" USB HDD (rpi3b-2.5drive)Basing on the rpi3 enclosure above, a 2.5" HDD can be installed in a very compact way.***Applications

• Raspberry Pi 3B - IoT FFT https://github.com/msonst/rpi-iotReal-time FFT via MQTT with one Raspberry PI Zero W + ADXL345 (high resolution 3-axis accelerometer) via SPI for data acquisition and one Raspberry Pi 3B+ with Node Red.

• Raspberry Pi 3B - Backup https://github.com/msonst/rpi-backupBacks up several machines to a local drive via cron-scheduled rsync.

• Raspberry Pi 3B - Nextcloud https://github.com/msonst/rpi-cloudProvides cloud features from your private network to your smartphone, Windows or Linux machine.

For RPI Zero please see https://www.cgtrader.com/3d-print-models/science/engineering/raspberry-pi-zero-w-enclosures