No one is really sure what a Xamek is, or if they even exist
Appearing as mutilated humanoids with large heads, Nihilids are terrifying to encounter. They are thankfully rare.
Dimensional Science has started to unlock the understanding of the fact that the universe is made of layers, and these layers while interacting with each other, are very distinct from each other.
What is arcanotech? It's breaking the laws of physics for fun and profit.
A hostile race discovered through dimensional boring. The first encounter with the violent and nomadic Tarxan occurred in Neo-Constantinople of the Eurasian Alliance, hence the Turkish/Central Asian rooted name.
"Living in a town that sits on a dimensional nexus can wear thin after a while. It's not so much the crawling shadows, bizarre weather, or late night visitors from places that never existed; but carrying on with your normal life and trying to act like nothing out of the ordinary is going on in your little corner of the world that gets to you."
A small rural town with surreal secrets, that happens to be situated on a dimensional crossroads, suitable for modern day supernatural/mystical/horror campaigns.
The Yugzhee, or "hedgehog-people", guard a great, secret treasure inside their giant burrowed lair. The mysterious Wall of Keys, a 12'x10', foot-thick, cold-iron, "wall", upon which, on iron hooks, hang 100 ornate iron keys of all shapes and sizes. Each key opens some heretofore un-openable barrier, door, or gate, in the particular game world of choice.
The PCs have come upon a great boon, except for the fact that the keys cease to function properly if separated from the iron wall for more than a few minutes. Higher level characters will be able to figure out how to take the wall "with them" via magic. Lower level characters will have to get creative.