It's not to say that horror movies copy each other (although we know they often do) but sometimes films can remind us of another one we had seen. I know some obscure horror movies that are similar in subject or feel to more popular movies. Here, I'm going to recommend some may-not-have-seen-it similars and a link to see them on YouTube.
If you liked "Village of the Damned" or "Children of the Corn," you might like the 1972 film with Kim Darby called "The People." A schoolteacher is hired by an isolated village to teach their "exceptional" children who might be otherworldly.
If you liked "Duel" or "The Hitcher," you might like the 1977 Valerie Harper film, "Night Terror." A housewife on a long-distance drive witnesses a man killing a police officer. She is then chased down by him as the only witness.
If you liked "The Stepford Wives" or "The Dark Secret of Harvest Home," you might like the 1987 Pamela Sue Martin film, "Bay Coven." A husband convinces his career wife to live on an island offshore where everything is idyllic.
If you liked "Andromeda Strain" or "28 Days Later," you might like the Peter Graves 1974 film, "Where Have all the People Gone?"
If you liked "Maximum Overdrive" or "Cujo," you might like the Leslie Nielsen 1977 film, "Day of the Animals." Hikers in the high country find that the thinning ozone has made the animals go mad.
If you liked "The Legend of Hell House" and "The Amityville Horror," you might like the 1978 Richard Crenna film, "The Evil." A psychiatrist buys a house in the middle of nowhere and gets friends and colleagues together to renovate it, only they are trapped inside the evil home for a very long night.