I ran two games, one with Tales from the Loop and another shorter one with for Things from the Flood.

The first one had a city with three main paranormal things going on:

• Premise is SCP 026. Some kids are missing, someone thinks they're being kidnapped. Truth: someone went in the abandoned school for a dare and later got back in the school and ended up trapped. Variation on the original scp to help the narrative: there is a mold infestation that has supernatural properties, it influences dreams and the perception of reality, the basement holds the root that can be destroyed with fire, but being exposed to the infestation alters one's perception of reality more and more (every body-force check failed they get one point of mental strain due to exposure). If the infestation is destroyed the people trapped there will be freed.
• Premise is SCP 105. A guy has been murdered, his SO is Iris Thompson. The way he has been murdered may either suggest that someone got into the house without him knowing, or it was Iris doing it with her powers (in my case during the game I decided that there was a co-worker of her boyfriend that killed him, but Iris was scared and asked the kids to help her prove it wasn't her).
• Premise is SCP 193. The mother of one of the kids is getting sick, although she gets better at home, when she works she feels way worse. Truth: near her workplace is a military base, scp 193 is an experiment from the secret base underneath that, and has recently managed to escape containment and now resides in the building where the mother works. Investigating it, it shows that it is a silicon based life form and can be killed, or at least made inert by exposing it to fire.
• Premise is SCP 1230. theme is darker because I set this mystery in the Things from the flood setting. There has been several suicides among kids recently and people in school talks about a mystrious magical book, one day a kid jumps from the top of the school and lands in front of the Teens and dies. For a second a green book is seen in their hands before disappearing. Truth: there is a book that with the words "A hero is born" on one page that when read will allow one person to experience very vivid dreams. A teenager ripped a page from the book and wrote "A hero died", and now he manages to enter other people dreams who read the book to manipulate them and inducing them to suicide. After the death, the book will go to another person (friend or random) and only them and the "killer" know the identity. The killer has the "hobby" to take pictures of the people before they die. The book can't be simply destroyed. If one of the players reads the book, a scenario specific to their background will appear in their dreams that night, but a boiling, black cloud will be brewing on the horizon, that is the corruption that the dreamer will experience in their dreams that will appear heroic, but too violent or crude and then degenerate to be more and more evil. The face of the killer will start to appear on random people in the dream.

SCP already seems like a great source. Its always fun to catch a glimpse of monsters as a teaser for that sort of game. I think some amount of sci fi can definitely enhance paranormal settings, but I understand not wanting to lean too much into that.

The Simon stalenhag books that the Tales from the Loop setting originated in may be very good inspiration for hooks. They have beautiful art with vignettes and stories from one or a few characters perspectives. Anything that is too sci fi can be swapped out for an equivalent paranormal phenomenon, or completely rewritten. The best part about them is that the stories are very minimal as to not distract too much from the art, this adds a lot of empty space for things to be added, which kinda makes it perfect for plot hooks. Also they art itself is gorgeous.

If you are looking for works functionally very similar to SCP, their sister site the Wanderer's library is much more fantastical/paranormal. It may be a step too fantastical, but adapting single elements from high fantasy stories is a good way to tease a deeper weirder world.

In podcasts you can checkout the Magnus Archives. It is a podcast about a fiction organization that is like a much less powerful and scientific version of the SCP foundation. Not much else to say than the stories are pretty good and might inspire good hooks.

My final moonshot recommendation would be... Take a stand ability from a weird random Jojo's bizarre adventure character, slap it on a hybrid of two cryptids, and you have a grade A paranormal creature escaped from a government lab. For example, a moth winged giant ape that can turn dead animals into other animals it can control, or maybe an alien loch ness monster that is appearing in multiple completely disconnected bodies of water by traveling through the reflections of a giant tower at the center of town.

Don't know if this is helpful or just rambling. Personally I think the tales from the loop setting is at its best when its a near 50/50 SciFi/paranormal so I wouldn't shy away from using tech to make things even spookier. Ghosts and machines don't mix well, but in a good way.