FHEM - FHEM (TM) is a GPL'd perl server for house automation.
SEQUEmatic - SEQUEmatic lets you build sequences to link together your various smart devices.
Conrad Connect - Service for managing smart home devices
Domoticz - Domoticz is a lightweight Home Automation System
Homebridge.io - Homebridge is a lightweight NodeJS server you can run on your network that emulates the iOS HomeKit...
Home - Securely control all your HomeKit accessories from your favorite iOS device.