Comment by Ajedi32

All of them, unless they're also on the list of examples to exclude (like the Downloads folder).

I think the point is that as long as the user is sharing things on purpose and not by accident, it should be allowed. Selecting the root of the home directory would probably share a lot of things the user didn't really intend to share (because a lot of apps just dump random config files and stuff in there), but if they specifically select a subfolder they probably have a good idea of what that folder contains.