Then there is the tromboon, created by P.D.Q. Bach, which is a real instrument but should not be.

https://en.wikipedia.org/wiki/P._D._Q._Bach#Tromboon

I don't know if Disaster Area's setup qualifies but it would be a fun entry for sure.

This collection is so cool

In this era, I think it won't be long before someone makes an AI music video featuring these instruments being played. I imagine the https://imaginaryinstruments.org/the-cat-piano-katzenklavier... would be quite entertaining to see.