Orange Pi 3B 4GB RAM DDR4 Rockchip RK3566 Mini PC Board Orange Pi 3 Model B WiFi Bluetooth BLE SBC Single Board Computer - AliExpress
Orange Pi 3B 4GB RAM Rockchip RK3566 Mini PC Quad-Core 64-bit WiFi+BLE Gigabit Run Android Linux OpenHarmony OS SBC Single Board - AliExpress
HB4IQ352GLVA SBC SINGLE BOARD COMPUTER W/4GB RAM & Core 2 Quad CPU Q9400 | eBay
Amazon.com: Rock Pi 4 Plus Model B Rockchip RK3399 SBC Single Board Computer eMMC Flash pre-Loaded with Twister OS Armbian Raspberry pi 4 (32G eMMc, No Heatsink) : Electronics
NanoPi R4S Headless SBC Supports Up To 4GB RAM and Features Dual Gigabit Ethernet and USB 3.0 Ports - Electronics-Lab.com
seeed Studio Raspberry Pi 4 Model B [4GB] RAM, Single Board Computer Suitable for Building Mini PC/Smart Robot/Game Console/Workstation/Media Center/Etc. : Electronics - Amazon.com
Rock Pi 4C SBC with 4GB RAM, HDMI and DisplayPort Launched for $59 and up - CNX Software
Orange Pi 5B 4GB RAM 32G EMMC 64-bit Rockchip RK3588S SBC Single Board Computer WIFI Bluetooth BLE Mini PC 5 B Development Board - AliExpress
Quartz64 Model B SBC with 4GB RAM is now available for $59.99 - CNX Software