So ones I've seen
Dr Who - Listen. Eerie, I think more than scary. I'm not one that generally gets scared at films or tv. Of all Dr Who episodes, both classic and new, the scariest for me is Midnight with David Tennant. It's a phenomenal performance from Lesley Sharpe, and the Doctor is helpless, indeed ostracised. I have an underlying phobia of madness and while this isn't explicit here, it's the base for the idea.
Buffy - Hush. Brilliant, funny, not scary imo. Given my fear of madness, Normal Again is the episode that plays on it most.
Ghostwatch - because it's played straight gets to be genuinely scary. The pacing in its brilliant. The only issue is the actress who plays the mother was too well known
The X Files - Home. Not scary to me, bit icky. Ice, another one that plays on madness works for me
Twin Peaks - Lonely Souls - the sequence covered is brilliant.
Mindhunter Series 1, Episode 2 - yep, scary but a bit worrisome, and obviously about madness. As Mindhunter is factually based, and Kemper and his crines are real, it creates an uncomfortable feeling. Part of why I stopped watching it after 1st series.
Stranger Things - The Weirdo on Maple Street - it's well done. Not scary
The Walking Dead - Seed. All a bit Doom. The Walking Dead is all a bit video game.
Fringe - Marionette - yep that's quite scary, and not very Fringe.