You know, I've seen cards where people just put them over the edge of an image, kind of between the image and the mat/frame around it. Usually they are the circular kind of paperclips, though.
I've also seen some cards where they use a paperclip to make the body on a die-cut butterfly which is attached to the card.
If they are large enough, you can make some cute bookmarks with them. I've done that. Here is a link to paperclip bookmarks:
Jumbo Paper Clip Bookmark | StampingSharon