Another one - going down stairwells alone in high-rise building. I always worry that somebody will pop out from behind a pillar, etc and chase me down the stairs with a knife, and I'd of course stumble and fall, etc etc.
Another is some random stranger in a crowd suddenly shoving me onto the railway tracks in front of a moving train.
Another is having someone coming up and throw acid at my face.
Another is someone shooting at me as they drive by, for the LuLz while I'm walking. Especially if I'm wearing red or blue (considered gang colors).
Or walking by a van and being snatched and dragged inside.
Oh. And someone infecting public restroom toilet paper with HIV semen on purpose.
Those aren't really strong fears, just random ones that pop up when I'm in an extra-paranoid mood.