4. '18' (RESTRICTED exhibition to adult audiences)
This list has been duplicated in Letterboxd. The Letterboxd version of the list only has films whereas in the IMDb version, it will only have TV shows (not individual episodes, just the entire show, and video games. Short films and music videos don't count.
Also, because TV shows have episodes, they may have different classifications, so I will be noting them down below and include them in other categories depending on how many episodes or which seasons are not worse than the higher episodes or seasons.