What 3rd party devices are supported?

Volumio born as open-source OS.

The first compatible and most performant 3rd party platform is Raspberry PI.

There are Volumio images available on www.volumio.com for the Raspberry Pi (RPI4 and model B+, Raspberry Pi 3 Model B, Raspberry Pi 3 Model B+, Raspberry Pi Zero, Raspberry Pi Zero W.),

The IMG file is also available for x86/x64 , Asus Tinkerboard platforms.