Aboleths that are just figuring out how to create skum. If it was a fairly non-fantastic world (low magic IOW), an invasion from the sea and under the earth would make a fine horror game.
The secret eaters from Minions control information by erasing memories and worship an unknown god. I can see a setting based on Dark City.
Another horror senario- kobolds that cause sinkholes. Their trapped tunnels could kill off all the experianced NPCs and leave the party alone in the middle of a battle they don't understand.
Giants that raid from their distant homes. Working together, hill giants raid and fire giants forge weapons and armor for both. The forge is found in a volcano and the party must esacpe before it erupts (yeah a bit cliched, but still useful).
Trolls of all shapes and sizes. Learn how to kill one and the others eat you.
The secret eaters from Minions control information by erasing memories and worship an unknown god. I can see a setting based on Dark City.
Another horror senario- kobolds that cause sinkholes. Their trapped tunnels could kill off all the experianced NPCs and leave the party alone in the middle of a battle they don't understand.
Giants that raid from their distant homes. Working together, hill giants raid and fire giants forge weapons and armor for both. The forge is found in a volcano and the party must esacpe before it erupts (yeah a bit cliched, but still useful).
Trolls of all shapes and sizes. Learn how to kill one and the others eat you.