FHEM - FHEM (TM) is a GPL'd perl server for house automation.
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Conrad Connect - Service for managing smart home devices
Gladys - An open-source home assistant powered by a Raspberry Pi 🗣️
Homebridge.io - Homebridge is a lightweight NodeJS server you can run on your network that emulates the iOS HomeKit...
SmartRent - Smart home automation for property managers and renters