Styrofoam, matches, cleaning chemicals, firecrackers, thunder, bugs, dogs, children and babies, being a passenger in a vehicle, the police, permanent markers, knives, pliers, toothpicks, nails, mag-lites/big flashlights... rebar, milk crates, nail files, hammers, showers, the rain, COVID masks (had to get over those), Smitty's and Steak & Stein restaurants, some hotels around here, some neighborhoods here/how the houses look, etc etc etc.
I mean some of this is super obvious and not weird at all when put in a list like this if you know me. But for day-to-day life it has looked very odd being afraid of a milk crate or styrofoam cup! Tbh, I think PTSD triggers are automatically idiosyncratic in that it's the defining feature of the disorder: what is benign, and this is individual/random, becomes a threat.
Guns trigger the f*ck out of me - that isn't idiosyncratic. If I told someone "I was in an armed group as a kid and now have PTSD" they would probably assume, without ever being told, that guns are a problem for me. But someone pointing a gun at me? Didn't trigger me. I stayed very calm and talked him through what would happen as a result. I did what he wanted and he ran off.
It was a trauma in the grand sense of the word but it still doesn't impact me that much. Launched my PTSD from other issues, but not that one. So that is idiosyncratic as well - what doesn't trigger me is equally as random.