ESPRESSObin - Electronics, Single Board Computer, and x86
Udoo x86 Ultra - Udoo x86 Ultra is a modern PC, known as the most powerful X86 maker board and an Arduino 101 compatible platform.
Olimex A64-OLinuXino - Open source hardware board that runs Linux and Android. Entirely designed with open source software CAD tools.
Intel NUC boards - Four-by-four inch Intel NUC boards come with a soldered-on processor.
esp32 - A very cheap small chip, compatible with Arduino.
Helios4 - The Open Source and Open Hardware Network Attached Storage (NAS). Build your own PrivateCloud: Store music and movies, share photo albums with friends, protect your files and never fear losing data again.