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.
Google Home - Set up, manage, and control your Chromecast, Chromecast Audio and Google Home devices.
Noizio - Feeling that the noise of the big city is too much for you to bear?
Sonos One - A self-contained, Alexa-connected speaker from Sonos
zenmix.io - Ambient background sound generator
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.