ioBroker - flexible and modular application for the IoT and Smarthome
My Devices - Drag and drop IoT project builder for Raspberry Pi
Nim Home Assistant (NimHA) - Nim Home Assistant is an open-source home automation platform running on Nim.
Domoticz - Domoticz is a lightweight Home Automation System
MisterHouse - MisterHouse is an open source home automation program.
SEQUEmatic - SEQUEmatic lets you build sequences to link together your various smart devices.