I'll let others be the judge of what is unusual.

A wide variety of pottery instruments are the subject of the book From Mud to Music (ISBN 978-1-57498-349-4)

Bart Hopkin has written several books and has invented a wide variety of instruments.

I found Tan Dun's performances of Paper Concerto and Water Concerto interesting.

I saw an interesting YouTube video about playing music on a Mason jar partially filled with water. https://www.youtube.com/watch?v=0XqwVciXa-w

Also on YouTube, I saw Evelyn Glennie play a jawbone of a donkey or some such beast. The teeth made a rattling noise. I didn't find Glennie's video, but here is a Led Zeppelin cover which includes the donkey jawbone. https://www.youtube.com/watch?v=AZMY-py8hb4

Yet another YouTube video. "Over the Rainbow" played on a cat organ. https://www.youtube.com/watch?v=GxEHi6Mlzmk

I just had an idea. I have seen molds used for growing vegetables to create a particular shape. Could such a mold be useful in forming gourds to be a consistent shape and size to make a standardized instrument?