I don’t remember where I heard this one from but another would be to hang fish hooks about head/eye level in areas of approach. Thin fishing line and hooks dangling from bushes and trees would be nearly invisible. You can contaminate them with your choice of materials. Blinding enemies or a facial wound that leads to sepsis is definitely a deterrent. Depending on the location of the wound, they could have a small scratch on their cheek that within hours could become inflamed leading to their face swelling essentially blinding them by inflammation.
The most important thing about trap placement is location. Always plan traps around concealment/ cover. Remove or destroy anything that could be used as cover during an attack. Anything that can’t be moved trap the hell out of it.