someone 3d printed a vegan violin. It sounds usable. Plenty of smaller instruments are made from clay (ocarina), metal (finger harp), wood (whistle), gourds (like maracas), etc. and you can even make your own! That’s how you’ll guarantee it’s vegan! There’s even a vegetable orchestra that makes instruments from foods. Once you start looing you’ll be amazed what you find. What if you go on a vegan musical journey? The vegan adventure awaits. In no time you’ll be up there with Paul McCartney riffing on the celery with the Beach Boys (i.e. the song Vegetables).
I’d really go the percussion route – the strings and brass are likely not going to help.
Oh yeah totally forgot – the body is an instrument all its own. You can sing, whistle, snap, etc. Play with what’s around you – spoons, washboard, trash can, etc. I mean a steel drum or hand pan is cool too! With the percussion and vocal route – singing vegan lyrics – it’s infinite what one can do!