Types of Thrillers
There are various kinds of thriller sub-genres, each bring a different element into the world of 'thriller films'.
Psychological - thrillers which are based around the idea of the mind. The plot is almost definitely based around one of the main characters, albeit bad, mental state.
An example of this is the film 'The Machinist' in which the entire film is based around the main character trying to come to turns with his insomnia. However, the film reveals his mental state is in shatters as his entire social life is basically a hallucination created from guilt.
Crime - thrillers which are based around the idea of criminal behaviour. The majority of the films follow street-gangs, mafias etc.
An example of this is the film 'The Departed', set in Boston. It revolves around an undercover cop in the Irish Mafia, and a member of the same Mafia undercover in the police force. The plot is based on both of the characters trying to discover who the other is, before they, them self, gets caught.
Spy - thrillers which are based around the concept of government agents, spies etc. There is a broad spectrum of plot ideas for a spy thriller, although commonly they involve: Double-crossing, identity crises etc.
An example of this is the Bourne Trilogy, a series of films based around a man who has forgotten his identity, through out the series, he uses a variety of spy tactics to overcome his enemies and find out his true identity.
Political - thrillers which are based around the government, or political parties. Commonly, these films revolve around terrorism, rogue government agents etc.
An example of this is the film the Manchurian Candidate . Which is based around a brainwashed political candidate, and terrorism.
Sci-Fi - thrillers which are based around science fiction. Due to the wide range of different Sci-Fi elements, the plot ideas are very wide-ranged as well, however, there is a very thin line as to when a Sci-Fi Thriller becomes just a Sci-Fi film. Sci-Fi Thrillers tend to have a more down to earth and realistic approach than Sci-Fi films.
An example of this is the film Limitless, in which a man digests a pill, thinking it will be just be a drug, such as ecstasy for example, however, it completely improves him as a person, it makes him smarter, more charismatic etc.
There are a variety of other Sub-Genres as well.