IndieWire's 100 greatest horror films of all time. After all of the updates (see below) Indie wire is back to a manageable list with many notable omissions.
www.indiewire.com/feature/best-horror-movies-all-time-scary-films-1202012183/

This is IndieWire's ranking of the 120 greatest horror films of all-time. As of April 10, 2021.
Edit: October 18, 2021. Indiewire has updated their list to *135 films.
*They include Inside twice on the list so there is only 134 unique films on this list.
Edit: March 23, 2022. Indiewire has updated the list to 150 films. They also fixed the error of having Inside listed twice.
Edit: July 16, 2022. Indiewire has updated the list to 155 films.
Edit: September 9, 2022. Indiewire has updated the list to 170 films. There is no number 78 on their list. Saw is on the list as number 167 but is in the 80th spot. The Invitation is listed as 167 in the 167th spot. Number 78-80 in this list is in the order of IndieWire's list and has the correct numbering as opposed to the error on IndieWire's list.
Edit: September 15, 2022. Indiewire has updated the list to 185 films. All previous issues corrected.
Edit: September 23, 2022. Indiewire has updated the list to 200 films. List is not in ranked order anymore, but instead chronological/alphabetical. 15 new additions added to end of this list in order of release year.
Edit: October 25, 2022. Indiewire has updated the list to 220 films.
Edit: November 15, 2022. Indiewire has updated the list to 225
Edit: August 9, 2023. IndieWire has updated the list to only 200. Indicating that they can add or remove films going forward.
Edit: september 17, 2024. IndieWire updated the list to only the 75 greatest horror films.
Edit: October 17, 2024. IndieWire can't help themselves and have to update this list again. Not sure what is wrong with them.