Invasion of the Body Snatchers Movies: Original Timeline
While the 1978 film is generally marketed as a remake, careful viewers have noted details that suggest it could be a stealth sequel to the original 1956 invasion. The key evidence is a memorable cameo by Kevin McCarthy, the star of the first film, who appears running through San Francisco's streets warning about the pod people - reprising his character's desperate flight from the original's ending.
This watch order treats the films as potentially connected, with the alien invasion spreading from the small town of Santa Mira to the major urban center of San Francisco. The connection isn't explicitly stated, making it subtle enough that the 1978 film works perfectly as either a remake or a continuation of the story.
There is 1 other watch order available - see the link up above.

Invasion of the Body Snatchers
A small-town doctor discovers that the residents of his community are being systematically replaced by emotionless alien duplicates in this classic science fiction thriller.

Invasion of the Body Snatchers
Two health department workers in San Francisco discover that the city's residents are being replaced by emotionless duplicates in this chilling sci-fi horror remake.
Other Film Series
Benson-Moorhead Universe
An interconnected indie sci-fi/horror universe from filmmaking duo Justin Benson and Aaron Moorhead.
Darkman
Sam Raimi's cult superhero-horror trilogy following a disfigured scientist who becomes a vigilante.
Friday the 13th
The murderous legacy of Crystal Lake and its iconic killer Jason Voorhees in this enduring slasher series.
H.P. Lovecraft
Feature film adaptations directly based on the works of horror author H.P. Lovecraft.
Phantasm
A surreal horror franchise following young Mike Pearson and ice cream vendor Reggie in their ongoing battle against the interdimensional Tall Man and his deadly silver spheres.
REC
Spanish found footage horror franchise following a demonic infection outbreak, featuring intense apartment building quarantine scenarios and their devastating consequences.