EarTrumpet - Volume Control for Windows
Google Home - Set up, manage, and control your Chromecast, Chromecast Audio and Google Home devices.
Volume2 - Volume2 is an advanced Windows audio mixer, a complete replacement for the standard Volume Control.
Sonos One - A self-contained, Alexa-connected speaker from Sonos
Sound Control - App-specific volume control
Home-Assistant.io - Home Assistant is an open-source home automation platform running on Python 3.