The Parallax View to JFK to Zodiac. The thriller sub-genre whose central material is the discovery of a hidden controlling structure.
Conspiracy thrillers are the sub-genre whose central material is the protagonist's gradual discovery of a hidden controlling structure underlying the visible events of the film. The form's foundational texts are post-Watergate American cinema (The Parallax View 1974, All the President's Men 1976, Three Days of the Condor 1975) — films whose central anxiety was that institutional power, in the Watergate aftermath, could not be assumed benign.
Conspiracy thrillers succeed when the conspiracy is structurally plausible. The form's best entries are those where the audience accepts the central conspiracy as the kind of arrangement that could actually exist; the most-canonical entries (Chinatown, JFK, Zodiac, Spotlight) all build their central conspiracies from real-world precedents or actual historical events. The films that fail are those that construct conspiracies too elaborate to credit — the audience cannot suspend disbelief because the proposed conspiracy structure exceeds what real institutional capacity could plausibly produce.