I'd probably have to do some research to get you a comprehensive list, but to start, anything with the name Hitchcock or Kubrick on it is a pretty solid bet, Jaws, Blade Runner if you like navel-gazing sci-fi shenanigans, the early Alien and Predator moves before things got shit, any of those monster movies I listed earlier...you can start looking at other shit by the same directors if you're really into the style of any of them.

[While this is mainly off the top of his head, there's definitely some kind of logic to it. Prolific franchises and prolific directors give him a good stepping-off point if he wants to dive further into the pits of classic cinematic hell.]