The 1970s and 1980s were horror movie lovers' heaven! There were movies about nature turning on man because of pollution, witches, devil worshippers, killers, insanity, revenge, demons, families moving into haunted houses, beasts attacking, and teens being slashed.
You might have missed some of the more obscure ones in the offering -
*Descriptions thanks to my favorite movie site IMDB(The Food of the Gods - 1976)
The Food of the Gods: A group of friends travel to a remote Canadian island to hunt, only to be attacked by giant killer animals which have populated the place.
The People: Kim Darby and William Shatner star in this 1972 made-for-tv movie. A woman is sent to a secluded valley to teach school to the reclusive residents' children. The citizens start showing some odd skills and pretty soon the teacher begins to wonder if the residents are human.
The Initiation: Daphne Zuniga stars in this 1984 slasher that takes place during an initiation stay in a mall when it's closed.
Bad Ronald: This 1974 gem is about a nerd who is picked on and kills his tormenter. His mother then hides him away in a room and then later dies and he is left in there while a new family moves in.
The Evil: This 1978 movie starts Richard Crenna and is a pretty cool ghost story that a lot of folks missed. A psychiatrist gets an old abandoned home to turn into a clinic and his friends and students help him renovate it, only to be locked inside with evil chasing them down.
Day of the Animals: This 1977 made-for-tv movie has a lot of stars in the lineup for a movie that includes Leslie Nielson as a would-be rapist. This is what happens when hikers face woodlands in another 1970s scenario of polluted earth and demented animals taking on revenge scenario.
The Screaming Woman: This is a very obscure and almost not even noted 1972 movie about a wealthy mental patient who retreats to her estate to recover. She hears a woman screaming from underground and believes someone is buried alive. The family, however, sees this as a chance to prove she is crazy.
Gargoyles: This 1972 movie is a cult classic. It involves an archaeologist, his photographer daughter and a trek through the desert to run into gargoyles who live in the caves and come out every few decades to cause trouble.
Something Evil: This is 1972 Steven Spielberg film is a made-for-tv variety of horror when a family (Sandy Dennis and Darren McGavin) move into a lovely country home to avoid the city and raise their kids, only to have the wife losing it and believing there is evil in their home.
Mark of the Devil: This 1970 obscure find is a true S and M kind of horror film that had a cult following in the 70s. It includes some pretty graphic stuff - woman's tongue being ripped out, nuns being raped. It disturbed many and yet it had a following. This movie deals with the witch trials and sorcery and angry villagers.
Children Shouldn't Play With Dead Things: This 1973 film has children digging up a corpse and making the dead rise from the grave.
The Demon Lover: This 1977 film has teens in a graveyard hanging with a demonic priest to raise up a demon from hell.
Terror In the Swamp: This 1985 has a scientist trying to come up with a new form of fur so that wildlife isn't endangered, only he develops a beast that roams the swamps.
Night of the Demon: This 1980 Bigfoot movie takes it to a new level of nastiness when a professor and his students go on a search to find that Bigfoot raped a teen and impregnated her with a mutant.