Noisli - Noisli is a fantastic background noise and color generator for working and relaxing. Online soothing ambient sounds like White noise, Rain and Coffee Shop.
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.
Noizio - Feeling that the noise of the big city is too much for you to bear?
ioBroker - flexible and modular application for the IoT and Smarthome
zenmix.io - Ambient background sound generator
openHAB - "empowering the smart home" - vendor and technology agnostic open source home automation