REC Movies: Quarantine Films
The Quarantine films represent American adaptations that reimagine the REC concept for English-speaking audiences. While the first film closely follows the structure and plot of the original REC, it exists as a separate continuity with different characters.
Quarantine 2: Terminal shifts the outbreak to an airport setting and is an original sequel specific to the American version. These films can be enjoyed independently without knowledge of the Spanish versions, offering their own take on the infection outbreak concept.
There are 4 other watch orders available - see the links up above.

Quarantine
A television reporter and her cameraman become trapped inside a building under CDC quarantine when a mysterious virus outbreak turns residents into violent killers.
Affiliate link - no extra cost

Quarantine 2: Terminal
When a mysterious virus takes over a passenger plane, the aircraft is placed under strict quarantine upon landing, forcing a group of survivors to work together to escape the deadly outbreak.
Affiliate link - no extra cost
Other Film Series
Bryan Edgar Wallace
A series of German crime thrillers produced by CCC Filmkunst in the 1960s-70s, marketed under the name of Edgar Wallace's son Bryan, featuring standalone mysteries with gothic atmosphere and masked killers.
Children of the Corn
A horror franchise following the murderous cult of children who worship a malevolent entity called He Who Walks Behind the Rows across multiple timelines and locations.
Edgar Wallace
German crime thriller series from 1959-1972 that created a distinctive subgenre of atmospheric gothic mysteries, featuring recurring cast and iconic villains.
H.P. Lovecraft
Feature film adaptations directly based on the works of horror author H.P. Lovecraft.
Invasion of the Body Snatchers
Four films exploring alien pod people replacing humans, each updating the concept for different eras and anxieties.
Unbreakable
M. Night Shyamalan's grounded superhero trilogy following ordinary people who discover extraordinary abilities, culminating in an unexpected crossover.