I was super sensitive as a child and could be freaked out very easily (still can, in a way). These are the main ones I can remember:
1. Lady getting turned into a robot in Superman - YES. Even though all that red stuff looks very plainly like ketchup, the way she got trapped in there was horrific. Even now I can't watch it.
2. Jaws from James Bond. The teeth, yes, but also just how LARGE he was and used to loom over everybody.
3. Daleks. My dad used to tell me it was safe to go to bed because a dalek can't get up the stairs because they had no legs
Which helped until I saw an episode where they beam themselves from one place to another. For some reason I remember that in the show they left a shadowy mark on the ground when they did this and at school in the playground the following day there were damp patches drying from the rain and I cried. (See also the Doctor Who theme tune, which still gives me the heebie jeebies.)
4. Slugworth from Willy Wonka. To this day men who have what I call "liver lips" like he did freak me out and look untrustworthy.
5. The theme tune to the South Bank Show. Hear me out! I think it was on about 10pm on a Sunday night and if I hadn't gone to sleep yet I could hear my parents watching it. I still associate with a sick and horrible feeling of the final countdown to school on a Monday morning (I was an anxious child) so it just became this musical theme to my dread of school.
6. When I was older, white bed sheets hanging on a washing line. Thanks, original IT movie!
7. The butcher counter
8. The TV productions of Helen Cresswell's Moondial (which had ghosts and kids doing time travel in it) and also the Box of Delights, which I believe was something to do with wolves?
9. WATERSHIP DOWN. And therefore also the voices of Simon and Garfunkel.
10. Finding a chick when cracking open an egg. Not sure of the origin of this but must be something to do with an urban legend or some
crappy story that appeared on the front of the Sun!