Cluster HAT Kit (includes 4 x Raspberry Pi Zero W)
Amazon.com: Dual Gigabit Ethernet Base Board Designed for Raspberry Pi Compute Module 4 or Being Integrated into End Products @XYGStudy (CM4-DUAL-ETH-BASE) : Electronics
Raspberry Pi — FarmBot
Raspberry Pi 4 Model B/2GB - PiShop.us
CrowPi Compact Raspberry Pi 4 3 Kit for Learning Computer Science and Master Raspberry Pi