Check out the 2021 Fiddlerman “White Christmas” Group Project.
I wrote a very nice cello étude in c minor, one that I really like. Since I don't yet have a cello, I transposed it to g minor and put it up in the violin's register. I can almost play this to tempo perfectly, so it isn't too difficult. I have a few problems with the stretches in measures 39 and 46, but this turned out to be a good étude for the violin as well. I'm not sure how I came up with something this beautiful - it saves as a humbling experience when I play or listen to this. I enjoy it so much that I just had to share the violin version with everyone here.