Very little, nowadays, but most stuff from Eric Ravn (metal/rock, somewhat famous for Wuthering Heights) [0] is not even available to buy other than as CDs that you order via HTML form ;) A few years ago, German medieval/folk band Die Streuner also wasn’t available on streaming services. Both have in common, that they have their own label.
[0]: https://nagelfestmusic.com/shop/