What is Speculative Fiction

Wikipedia1 says it best, with plenty of examples:

FantasyIncludes elements and beings originating from or inspired by traditional stories, such as mythical creatures (dragons, elves, dwarves and fairies, for example), magic, witchcraft, potions, etc.The Lord of the Rings, The Chronicles of Narnia, Harry Potter, A Song of Ice and Fire, How to Train Your Dragon
Science fiction (sci-fi)Features technologies and other elements that do not exist in real life but may be supposed to be created or discovered in the future through scientific advancement, such as advanced robots, interstellar travel, aliens, time travel, mutants and cyborgs. Many sci-fi stories are set in the future.The Time Machine, I, Robot, Dune, Star Trek, 2001: A Space Odyssey, Planet of the Apes, The Left Hand of Darkness, Star Wars, Blade Runner, Jurassic Park
HorrorFocuses on terrifying stories that incite fear. Villains may be either supernatural, such as monsters, vampires, ghosts and demons, or mundane people, such as psychopathic and cruel murderers. Often features violence and death.The Exorcist, A Nightmare on Elm Street, Books of Blood, The Hellbound Heart
UtopianTakes place in a highly desirable society, often presented as advanced, happy, intelligent or even perfect or problem-free.Island, Ecotopia, 17776
DystopianTakes place in a highly undesirable society, often plagued with strict control, violence, chaos, brainwashing or other negative elements.Brave New World, 1984, Brazil, The Handmaid’s Tale, The Hunger Games
Alternate historyFocuses on historical events as if they happened in a different way, and their implications in the present.The Man in the High Castle, The Last Starship from Earth, The Tales of Alvin Maker, The Guns of the South, Fatherland
ApocalypticTakes place before and during a massive, worldwide catastrophe, typically a climatic or pandemic natural disaster of extremely large scale or a nuclear holocaust.On the Beach, Threads, The Day After Tomorrow, 2012
Post-apocalypticFocuses on groups of survivors after similar massive, worldwide disasters.The Stand, Mad Max, Waterworld, Fallout, Metro 2033
SuperheroCenters on superheroes (i.e., heroes with extraordinary abilities or powers) and their fight against evil forces such as supervillains. Typically incorporates elements of science fiction or fantasy, and may be a subgenre of them.DC Universe, Marvel Universe, Kamen Rider, Super Sentai, Metal Heroes, Power Rangers
SupernaturalSimilar to horror, it exploits or requires as plot devices or themes some contradictions of the commonplace natural world and materialist assumptions about it.The Castle of Otranto, Weaveworld, Imajica, Paranormal Activity, Fallen

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