Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Intel NUC boards - Four-by-four inch Intel NUC boards come with a soldered-on processor.
ioBroker - flexible and modular application for the IoT and Smarthome
ESPRESSObin - Electronics, Single Board Computer, and x86
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
Udoo x86 Ultra - Udoo x86 Ultra is a modern PC, known as the most powerful X86 maker board and an Arduino 101 compatible platform.