Chronological. Subject to constant change. I ran a 2018 horror poll for Cinematary and wrote some thoughts on the genre therein: check it out.
Top 10
Dracula (Tod Browning, 1931)
Frankenstein (James Whale, 1931)
White Zombie (Victor Halperin, 1932)
The Black Cat (Edgar G. Ulmer, 1934)
House of Wax (André De Toth, 1953)
The Curse of Frankenstein (Terence Fisher, 1957)
Torso (Sergio Martino, 1973)
The Texas Chain Saw Massacre (Tobe Hooper, 1974)
Prince of Darkness (John Carpenter, 1987)
Loft (Kiyoshi Kurosawa, 2005)