Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
T-Clock Redux - T-Clock Redux in an enhanced fork of Stoic Joker's T-Clock 2010 with ISO week number support...
ioBroker - flexible and modular application for the IoT and Smarthome
DS Clock - Keep your time synchronized with Atomic Time servers, using customizable digital desktop clock with westminster chimes.
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation
AlarmDJ - Online Alarm Clock - Use YouTube videos or MP3 files as alarm sound. Works offline.