Horror movies

[Host-in-the-Shell]

Putting the modern era aside (horror made after the year 2000), I tend to separate horror into six big blocks, so I will list some films that are representative and quite recommended to watch for each.

• Silent era (Films without sound, usually made before 1931): The Cabinet of Dr. Caligari (1920), Nosferatu: A Symphony of Horror (1922), The Phantom of the Opera (1925).
  
• Classic era (Films with sound made from 1931-1949, usually monster pictures or The Old Dark House trope): Universal Horror Monsters (Dracula [1931], Frankenstein trilogy from [1931-1939], The Mummy [1932], The Wolf Man [1941]), The Old Dark House (1932), Vampyr (1932), The Black Cat (1934), The Raven (1935), The Man They Could Not Hang (1939), The Body Snatcher (1945)... and so many more, but I'm going to stop here to not be too overwhelming
  
• The Science Fiction era (usually monster flicks from the 50s that lean heavily on Sci-Fi and might constitute more of that than actual horror; definitely features the most "popcorn" films on this list, but will list in bold what I consider cinematic classics that shouldn't be skipped): The Thing from Another World (1951), It Came from Outer Space (1953), Invaders from Mars (1953), The Beast from 20,000 Fathoms (1953), Godzilla (1954 film), Invasion of the Body Snatchers (1956), The Blob (1958.), The Fly (1958.). I'd also recommend some William Castle films for non Sci-Fi horror of the time such as House on Haunted Hill (1959) The Tingler (1959).
  
• The Psycho era (films from 1960-1967 that became more edgy and took more risks thanks to the success of Psycho. It also featured the return of tropes from the classic era such as ghost stories and haunted mansions): Psycho (1960), Peeping Tom (1960), The City of the Dead (1960), Village of the Damned (1960), The Innocents (1961), The Haunting (1963 film), The Raven (1963), Black Sabbath (1963), The Tomb of Ligeia (1964), Repulsion (1965).
  
• The Satanic Panic era (Films from 1968-1977 that often featured Demonic themes; also notable for the rise of the zombie film with 1968's Night of the Living Dead, and for featuring some proto-slashers like The Texas Chainsaw Massacre (1974) and Alice, Sweet Alice (1976); for this one I won't recommend much films since you already seem familiar with some): Night of the Living Dead (1968.), Rosemary's Baby (1968.), The Exorcist (1973), Jaws (1975), The Omen (1976), Martin (1977).
  
• The Slasher era (from 1978 with the release of Halloween until around Scream's release in 1996, but I do extend it to 1999 since some slasher films still were quite popular until the end of the Millennium such as I Know What You Did Last Summer (1997), Urban Legend (1998.) and a plethora of sequels of other slasher franchises; won't recommend any films here since you seem very familiar with this block).
  

Keep in mind that this is no complete list and I consciously left out stuff like the Hammer horror catalogue, giallo horror films, Japanese horror and much more just to not complicate things. Hope this can prove useful for you.