Kodi - Kodi is an award winning free and open source media player that got its start on the Xbox console.
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Universal Media Server - Universal Media Server allows you to host your entire library of video, music, and pictures, and broadcast them conveniently to a wide variety of different devices.
ioBroker - flexible and modular application for the IoT and Smarthome
Serviio - Web on Big Screen. Serviio enables playback of online sources like RSS feeds, live streams or web site content so that you can listen to your favourite podcasts or watch latest TV programmes published online.
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation