Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
ioBroker - flexible and modular application for the IoT and Smarthome
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
SmartThings - SmartThings makes it easy to turn your home into a smart home.
Home - Securely control all your HomeKit accessories from your favorite iOS device.
Domoticz - Domoticz is a lightweight Home Automation System