Nor will it ever exist.
This index page (which does not exist), is about everything non-existent. Beyond the veil of our perceived reality lies the great void of non-existence. Largely, it is science fiction that employs these tropes, as it is a common and popular theme is to bring into question whether or not our reality is really real.
Non-existence or 'nothing' can be used as a force in its own right, to build suspense, drama or used as a break from material things such as bright colors or loud noises. Negative Space or a vacuum is a good narrative tool for painting the boundaries for situations or to isolate worlds or characters. Things that don't exist can major points of interest in many genres and mediums.
These tropes do not exist: