Intel NUC boards - Four-by-four inch Intel NUC boards come with a soldered-on processor.
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 - Intel NUCs are available as Kits(Barebones), Boards(Mainbaord only) and as perconfigured Mini-PCs.
MikroTik RouterOS - The main product of MikroTik is a Linux-based operating system known as MikroTik RouterOS.
esp32 - A very cheap small chip, compatible with Arduino.