openHAB is a Java-based open-source home automation platform that integrates and combines a vast range of different smart home systems and technologies into one single solution.
ioBroker is an integration platform for the Internet of Things, focused on Smart home, Building Automation, Smart Metering, Ambient Assisted Living, Process Automation, Visualization and Data Logging. It aims to be a possible replacement or extension for software like f.e.
Homebridge is a lightweight NodeJS server you can run on your network that emulates the iOS HomeKit API. It supports Plugins,community-contributed modules, that provide a basic bridge from HomeKit to various 3rd-party APIs of "smart home" devices.
CometVisu is a realtime visualization software using modern web technologies for building automation. It shows different statuses of a building and allows the interaction with it (like temperature set point).