If you're working in any kind of creative field, the one question you are absolutely going to be asked at some point is "Where do you get your ideas from?".
The answer is going to change based on the person and the genre they write. It can come from inspiration, imagination, perspiration, or even inebriation. It could even come from any combination of those things and even more.
This is a Horror blog though, so that's what I'm going to focus on, otherwise I'm probably going to start rambling on and on.
Stories of Horror are typically based on things like fear and death. As such, there are any number of things in the world (or supposedly in the world), that would grant inspiration for such stories.
The nightly news, for example, is well known for being a well upon which one can draw stories of horror. It is commonly said of the news these days that "if it bleeds, it leads." Which is, rather unfortunately, true for the most part. The head-on collision that kills a family of four, while the drunk driver that caused it escapes with just a few bruises. The man who walks into a local supermarket, and randomly opens fire, killing three and wounding a dozen others. The quiet house in a regular neighborhood, suddenly raided by the police as a meth lab. The horrific virus which is rapidly spreading beyond borders. The night news regularly covers dozens of real-life stories that could easily become something even more horrific.
That might hit a bit too close to home though for some people. In that case there's things a bit further outside the realm of everyday life. Rogue animals, that have taken an active interest in turning the tables on human hunters. Sharks, bears, wolves, giant squids. Of course, in this category, there's all the cryptids I've mentioned on this blog previously. Thunderbirds, sea monsters, lake monsters, bigfoot, and others.
To stretch things even further, you have the mythological creatures. Vampires, werewolves, zombies. Although I would recommend steering clear of those unless you have a take you know is fairly original. Ghosts fall into this category as well, but they aren't as overdone at the moment as the others are.
You can even mix and match different ideas to make wildly different stories. Like the man that walked into the supermarket and opened fire was possessed, or maybe he was infected with a virus after being bitten by a Chupacabra! So many ideas listed just in this small post alone. That's not even counting ideas which may be original, with their own monsters and threats.
And none of that is even close to the two-word idea that so many books start with.
So where do my ideas come from? All of these places. My first book was a "What if..." story. My second was actually an "I can do this story better." idea. "Hannah" is based on the mash-up of two ideas to make something relatively new, Cujo + The Exorcist, respectively. And of course, my book "Cenote" was based on the Lusca.
In the pipelines I have a stories I'm working on based on the Chupacabra, Megalania, and the Ropen. I've also got outlines done for a two-book series, one with a psychotic maniac, and the other with a haunted house.
So the ideas are out there.
Go find one and make it yours.