I tried to pick out the best ideas.
Deter Them:
Shriekers are scary so maybe they will get scared if we have things that make shrieking noises and go away.
Mind Flayers to confuse them so maybe they will go away.
Other Stuff:
Spiders: They have webs so they could trap them?
Boneyard/wall: Dead stuff that was killed with traps.
Soul Catcher: I don't know if we believe in alien ghost type things but if they exist this will catch them somehow I guess.
Armagio: Attacking creatures will attack this instead.
Catapult/Long Bow: These make the most sense out of my ideas because they can be readily used in real life traps. I don't know what the trigger would be though.
Lightning Storm: Electric field to zap things that get too close.
Steel Golem: Robot that kills things.
Lava Destroyer: Like steel golem but more sci fi like.
Cloak: For hiding against stuff.
Electrocutor: Like lightning and lightning storm and stuff.
Combo Ideas:
Lightning+Phase Spider
Net that is electrified.
Spider+Catapult/Long Bow
Spider makes web, when something disturbs the web it triggers the catapult/long bow.
It's super inconvenient to use spiders for triggers and nets. The spider might kill itself by disturbing the web in the second trap. Maybe phase spiders can be immune to their webs that have been electrified because they're not grounded.
Weird Idea
Flooding/maybe water pillar/tower+Gravity Force+Lighting
Gravity Force thing makes a wall of water that is electrified.