For what it's worth, if you don't have the chip that powers this card, there's also the PicoGUS which is a multi-function, software-defined ISA card that includes the ability to emulate the Gravis Ultrasound among other sound cards: https://picogus.com/

I have a PicoGUS and have had a lot of fun futzing around with Claude and porting Cave Story to DOS [1] the last couple of months after SDL announced DOS support.

Originally I was just using it as a Soundblaster, but in the last few weeks added Waveblaster, Adlib, and Gravis Ultrasound support. It's been a lot of fun learning how the GUS works and hearing how distinctively different it is from other sound hardware of that era.

1. https://github.com/ecliptik/doskutsu

Seems like the chip is available here: https://www.utsource.net/itm/p/762821.html?srsltid=AfmBOoraT...