Last summer I have worked on AMCtoOwncloud, a Nautilus script that sends annotated papers to OwnCloud/NextCloud and share them with students.
Since then, I don't send emails anymore. The students have an OwnCloud cloud account, so a folder is shared with them (otherwise I could also give them a share link).
I know it's a very specific usecase (for now, you need linux and the Nautilus file manager), but it can be convenient.
Feel free to ask if you are interested !