Here is a short collection, all either obtainable from services like VODO, The Pirate Bay or Public Domain Torrents.
For those who prefer to watch via their web browser, YouTube has a selection of free horror movies here.
Night of the Living DeadThe plot of the film follows Ben Huss (Duane Jones), Barbra (Judith O’Dea), and five others trapped in a rural farmhouse in Pennsylvania while the house is attacked by reanimated corpses, commonly known as ‘ghouls’ or ‘zombies’. Night of the Living Dead is the origin of six other Living Dead films directed by George A. Romero. (IMDb)
The TunnelIn 2007 the New South Wales government suddenly scrapped a plan to utilise the water in the disused underground train tunnels beneath Sydney. In 2008, chasing rumours of a government cover-up and urban legends surrounding the sudden backflip, investigative journalist Natasha Warner led a crew of four into the underground labyrinth. They went down into the tunnels looking for a story – until the story found them. (IMDb)
The Little Shop of HorrorsClassic black comedy about young schnook who develops a bloodthirsty plant and is forced to kill in order to feed it. Directed by Roger Corman, the film was the basis for the later hit stage musical.
Driller KillerAn artist slowly goes insane while struggling to pay his bills, work on his paintings, and care for his two female roommates, which leads him taking to the streets of New York after dark and randomly killing derelicts with a power drill. (IMDb)
The Phantom of the OperaA mad, disfigured composer seeks love with a lovely young opera singer. (IMDb)
Other viewingTo see the full range of Public Domain Torrents’ free and legal horror movies, click here.
The Internet Archive also has a horror/sci-fi section, as does Open Culture.