Things I was frightened of as a child:
Original Open University theme
The Blue Peter Ship heading straight towards you at speed at the very end: youtu.be/j_odGAcqoPU?...
Sapphire and Steel (series)
Mastermind theme (Approaching Menace; still surprisingly scary to this day)
Plus all the usual...
youtu.be
Blue Peter end titles - October 1982
YouTube video by LukkoZeroSix