Several outlets have published lists of highly-regarded sci-fi movies, including those from the 1990s and more recent releases. The lists vary in focus, with some highlighting specific subgenres, such as erotic sci-fi or sci-fi horror, while others provide more general rankings of the best sci-fi movies of all time or from a particular time period. It is unclear which specific movies are being recommended or ranked as the best, as the lists appear to have different criteria and selections.