A number of standalone horror movies deserved their own franchises, but the reasons why these properties didn't take off vary from film to film. Many of them actually had planned sequels that are still just lingering in development hell, with some seeing years and even decades passing now without any significant updates. Meanwhile, there are also cult movies celebrated only by a niche amount of loyal followers, and they have little hope of being considered by studios or financial backers for their non-mainstream appeal. However, even box office success and critical acclaim can't guarantee that a great horror film will get expanded into a franchise.

Indeed, numerous underrated horror films that deserve a sequel or an entire franchise can be found throughout the history of cinema. For one reason or another, these beloved movies never manifested any follow-ups. In rare cases, however, some of them may soon finally get their own sequels, prequels, reboots, or series adaptations.

10 Killer Klowns From Outer Space (1988)

Two years before the miniseries adaptation of Stephen King's IT, 1988's Killer Klowns From Outer Space gave audiences not one, but several murderous clowns. In tribute to '50s creature feature B movies, its clowns are really aliens, complete with circus-themed technologies and colorful methods of killing. Cotton candy, shadow puppets, balloon animals, and other party favors turn into murder weapons as the killer clowns ravage a small town. While the movie inspired a video game, it never got any film sequels. However, apart from being a horror movie that deserved its own franchise, Killer Klowns From Outer Space is also iconic among sci-fi movies so bad they're good.

9 World War Z (2013)

Brad Pitt looking at ruined city from a helicopter in World War Z 2 poster.

Starring Brad Pitt and featuring overarching themes that violently pulled the zombie genre back to its classic sci-fi roots, World War Z was a blockbuster success and a breath of fresh air in a decade saturated with generic content involving the living dead. From how the movie ended to the untold stories from the book on which World War Z is based, there's so much groundwork for not just a sequel, but an expansive franchise beyond this film. When it comes to standalone horror movies deserving their own franchises, World War Z is actually a popular example because of the highly anticipated and long-delayed follow-up almost directed by David Fincher.

Related: Why World War Z 2 Is Taking So Long & Will It Happen?

8 Shaun Of The Dead (2004)

Simon Pegg and Kate Ashfield look bewildered in Shaun of the Dead.

Out of all the standalone horror movies that deserved their own franchises, Shaun of the Dead is the only one that's recognized as the definitive comedic take on the zombie genre. With the titular Shaun keeping a zombified Ed secretly locked up at home so that they can keep hanging out, the movie's ending already lays the foundations for a sequel or two. Audiences have no doubt that the trio of Edgar Wright, Simon Pegg, and Nick Frost is more than capable of turning the movie into a franchise. In this case, however, Simon Pegg says Shaun of the Dead 2 will never happen because he'd rather make new movies.

7 The Loved Ones (2009)

Lola tortures Brent in The Loved Ones.

After high school student Brent turns down Lola's invitation to prom because he has a girlfriend, she and his father kidnap him to torture him at home, which they've decorated to look like a high school dance. Sick, demented, and sometimes hilarious, The Loved Ones is an underrated masterpiece that takes the teen slasher subgenre to offensive levels. Yet, its uniquely depraved themes are precisely why The Loved Ones deserves a place alongside standalone horror movies that deserved their own franchises. Lola and Eric may be dead at the end, but it's easy to imagine their legacy continuing through copycats, giving the Saw franchise a run for its money.

Related: How The Loved Ones & The Devil's Candy Overlap

6 Identity (2003)

Ray Liotta and John Cusack look inside a vault in Identity.

Starring John Cusack, Ray Liotta, and Alfred Molina, Identity is about 10 strangers stranded in a motel, where they are killed off one by one. However, Identity isn't like any other murder mystery. Alongside this main plot, Identity also tells a parallel story about a murderer awaiting the verdict of his trial. Combined with flashbacks to moments before the characters became stranded, Identity employs a reverse chronology structure that pays off in dividends in the third act. With Identity's cult following still debating what happens after the movie's big finale twist, this is definitely a standalone horror movie that deserves its own franchise.

5 The Wailing (2016)

The Wailing Stranger in Demon form

Na Hong-jin's The Wailing not only combines several horror subgenres but even uses these thematic elements to create truly unexpected twists. While it begins as a zombie virus movie, the story eventually tackles demonic possession, ghosts, shamanic and religious rituals, and even has an undercurrent of racial politics. Few standalone horror movies deserve their own franchise more than The Wailing, the most creative microcosm of Korean horror storytelling from the 2010s. The Wailing's twists end with the demon and the shaman getting away with everything and going off to the next town to pull their scam again. This story needs to continue in a movie or streaming series.

4 Dead Alive/Braindead (1992)

Lionel Cosgrove in Braindead Dead Alive

Before he became the Academy Award-winning director of the Lord of the Rings trilogy, Peter Jackson made the splatter horror comedy Braindead (also known as Dead Alive in the U.S.). The film follows the fate of a Sumatran rat-monkey, the progeny of a tree monkey, and a plague-ridden rat whose bite creates the first of many zombies. Braindead bombed at the box office but has since garnered a cult following hailing the movie for its hilarious extreme gore, plot, and creative body horror. Lovingly regarded as the most disgusting movie ever made, Peter Jackson's Braindead may just be what the zombie genre needs today.

Related: 10 Ghoulish Facts About Peter Jackson's Zombie Flick Braindead

3 Constantine (2005)

Keanu Reeves smoking in Constantine

Constantine gave viewers the first live-action version of the titular occult expert from DC Vertigo's Hellblazer comics, memorably played by Keanu Reeves in the action-driven big-screen adaptation. Many more DC Vertigo stories and characters have since been adapted into various successful live-action movies and series. Though NBC released a Constantine series, it was canceled after one season and wasn't connected to the original movie. Like many standalone horror movies that deserved their own franchises, however, 2005's Constantine could see a sequel soon — though it might be some time before audiences get an actual release date for Constantine 2.

2 Big Legend (2018)

Tyler and Eli worriedly looking around the forest in Big Legend.

Although it came out to mixed reviews, Big Legend is the only recent horror movie about Bigfoot with actual franchise potential. Despite centuries-old Chinook bone markings indicating that parts of the forest are off-limits, modern hunters trespass and encounter the mythical creature. These encounters and fights are extremely well done for an independent horror film, and it's the best modern horror interpretation of what it would be like to be terrorized by the North American cryptid. With the surviving heroes teaming up with more hunters to form a team to pursue the beast in the end, Bigfoot could be the next big horror action franchise.

1 Event Horizon (1997)

A closeup shot of Miller in Event Horizon.

Decades after its release, Event Horizon remains a divisive movie, with some saying its unique twist truly unified horror and sci-fi in the '90s, and others dismissing it as a B movie. What's less contested, however, is that Event Horizon has a place among standalone horror movies that deserved their own franchises. While many movies, series, and video games have merged sci-fi and demonic elements, none have matched the movie's premise of space travel technology inadvertently tearing open a portal to Hell itself. With today's special effects, Event Horizon could pave the way for the greatest sci-fi/horror series ever — unfortunately, the Event Horizon TV show has not yet materialized.