This is a Gnome Shell Extension that allows you to hide the devices that you do not need in the Quick Settings Audio Panel. It supports both output and input devices. It makes it easier to switch fast between your audio devices when the panel is decluttered from the entries you're not going to ever choose anyway.
The shown/hidden devices may be configured via preferences window.
Note that the extension does not disable the device in the system. All the devices are still going to be visible in the Control Panel. All this extension does is to hide the unneeded devices from the Quick Settings panel.
This extension does not play well with the Quick Settings Audio Panel extension. Its option to "Always show microphone volume slider" might not work when Quick Settings Audio Devices Hider is enabled. A workaround could be to install [QSTweak] Quick Setting Tweaker, which has a similar functionality under the toggle "Always show input" under the "Input/Output" tab.