Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
Google Home - Set up, manage, and control your Chromecast, Chromecast Audio and Google Home devices.
SmartThings - SmartThings makes it easy to turn your home into a smart home.
ioBroker - flexible and modular application for the IoT and Smarthome
Domoticz - Domoticz is a lightweight Home Automation System