Satanic panics started around the 1970s, when there was a rise in fundamentalism. They took full effect in the 1980s, 1990s and early 2000s. Today, few remain in the outside world, but the community is still prevalent on the internet.
The Illuminati conspiracy was started by some person who claimed to be a Satanist, but was later proven a faker.
Alledged backmasking in popular music, notably rock.
Some players of Dungeons & Dragons took the game too far and died, leading many to believe D&D was inherently evil, and that the game involved calling real spirits to possess people.
The Smurfs was apparently burning down villages in Puerto Rico and teaching children witchcraft.
During the Pokemon craze, several Christian groups alledged that the game was about channeling evil spirits into children and that the type system (ex. fire, water) was teaching people into becoming neopagan witches.
Tinky Winky, the purple Teletubby, was apparently gay for being purple, carrying magic bags and wearing a tutu, and therefore alleged to make kids gay.
Harry Potter was apparently telling children that witchcraft is real and encouraging children to become sorcerers.
Yu-Gi-Oh was programming children to become Satanists and Freemasons.