Hmmm why no Character Artist or CA3 tag?
So where might I find some more instruments for my bard ?
Lack of tag is just an oversight. I've added a 'Character' tag now. You can edit your post to add it if you wish.
As for music instruments, I don't think there is any available except for the harp. Maybe one of the free community symbol sets have symbols seen from the correct angle that it might be used. I don't think there are any Character Artist compatible symbols, but a top-down dungeon-scale symbol might work. Likewise, you may find an image on the internet which is usable.
If you were willing to use the older style Character Artist options, there's a greater range of instruments, albeit that's somewhat relative - a bell, a horn and a lute! The missing horn and lute in CA3 do seem rather an oversight, but then we've discussed endlessly on the Forum about ALWAYS wanting MORE symbols for everything 😁