I've used sticks, rocks, shrubs, tied to a loop on my pack and set it far enough out to tension (wasn't expecting rain that night ) While sleeping on boulders I have used what was essentially a stick jam to hold some line in a crack. I have been dying to use this but haven't needed it yet.

Necessity is the mother of invention. Once you're forced to make something work in your spot... or if you want the spot bad enough and you cant sink a stake for some reason you will come up with something to suffice for the night.