Tiny Library previously ran Kickstarter’s for a deck of one card RPGs and a book of one page RPGs, either of which are excellent collections for trying new games.
This time around they are crowdfunding a deck of concepts and interchangeable rules you can mix and match to customize a unique game session with your players.
All the cards in the deck are themed around Modern Fantasy (Settings like Stranger Things, Control, Unsleeping City, Supernatural, Buffy, or X-Files)
They are using a design system called MOSAIC where each card has to be able to function as a part of a larger game without knowing what the rest of the cards are.
Full details of the Game Jam used to select the 51 cards can be found here
https://itch.io/jam/tiny-library-tiny-library-mosaic-modern-fantasy
It’s a pretty cool system and encourages a GM to collaborate with their players in choosing the ruleset for an upcoming adventure, and contains new systems for things like death saving rolls, climax resolution systems, and magical subway transit that you may want to carry over to other games.
Best of all, a lot of the cards lean heavily into the spooky vibes of this time of year.
https://gamefound.com/en/projects/long-tail-games/tiny-library-modern-fantasy