The Gorgon is a monster from Greek mythology. A woman, cursed by the gods. Her body takes on several serpent-like characteristics, which vary from story to story. Some have snakes for hair, some are venomous, others have snake bodies from the waist down. All have the ability to turn other people to stone, either with the power of their eyes, or just by being looked upon directly. They're also commonly portrayed as master archers or even magic-users.
To be honest, I couldn't find any good novels to recommend where a Gorgon is used in any concept outside of appropriation of the name. It really strikes me as odd. You would there there would be at least a couple books I could suggest. Some romance writer could even take a Gorgon and make them the tragic main character, looking for love but unable to because looking upon her normally turns everyone to stone. There really seems like there is a lot of potential here that is going to waste.
Nocturnal, small, stone demon-like monsters. What's not to love. A solid facet of gothic architecture, they adorn buildings around the country in their thousands. Despite their ferocious appearance though, they are supposed to be symbols of protection. Warding off evil and harmful magic. There is also the idea that they come alive at night, making them a perfect substitute for the other denizens of the dark like werewolves and vampires.
Again, there's really a lot here to work with, and while there are stories to be had, including Gargoyle Knight by William Massa, there is so much that could be done here. A story could be based on their appearance and portray them as evil, gremlin-esque, monsters. They could be used as guardians and protectors against a powerful evil. Maybe the horror is in how they're created, or what happens when one is carelessly smashed. As I said, there is so much to work with here, I'm surprised pickings as so slim.
I know what you're thinking. Wait. What? But, yes, the Grey aliens are woefully underrepresented in fiction. I don't know why either, they are perfect antagonists for a sci-fi/horror story. What is more terrifying than the idea of something coming into your home, locked doors and windows ignored, swiping you out of your bed and using you to conduct experiments like a giant hairless lab rat? That's not even mentioning the advanced technology they wield.
Really. The books on the Grey aliens are mostly expose`, "true story" books. And almost every sci-fi movie ever done has been novelized. There are whole series based on the Alien franchise. The Grey aliens need some love too, though. After all, what could be more horrifying than looking out your window late one night, and seeing that bald, white head with those two big eyes staring back at you?
Of course, that just scratches the surface. Other possibilities in just Greek mythology include Minotaurs, Harpies, Sirens, and Satyrs. All with their own styles and abilities, with which any number of stories could be drawn from. There's literally hundreds of different monsters and creatures out there which are sorely unrepresented in fiction, there's no reason to continue rehashing the same three creatures over and over again.
But, it's a fad! If you want to make money, you have to get on the bandwagon!
Fads come and go, and by the end, people are getting pretty sick of them. It might seem like the way to make money is to throw shit at the same wall everyone else is, but you'll notice the stuff you threw quickly gets buried in the avalanche. You should also note that by the time you've noticed there's a fad going on, it's well into it's swing. By the time you've thought "Hey, I need to get in on this!", written your book, gotten it edited, and procured cover art, six months have gone by. If you're lucky. If you're on the traditional publishing route, it could be a year or more before your book finally hits shelves. Both are plenty of time for a fad to cool down.
In the meantime, instead of chasing after the wagon trying to catch up, you can write what you want. Do something everyone else isn't doing.
Who knows, you may even start a fad of your own.