Novels:
* Hercule Poirot Series:
* The Mysterious Affair at Styles (1920)
* The Secret Adversary (1922)
* The Murder on the Links (1923)
* The Big Four (1927)
* The Murder of Roger Ackroyd (1926)
* The Mystery of the Blue Train (1928)
* Alibi (1926)
* The Murder at the Vicarage (1930)
* Murder in Mesopotamia (1936)
* Death on the Nile (1937)
* Appointment with Death (1938)
* Murder is Easy (1939)
* Cards on the Table (1952)
* The Clocks (1963)
* The ABC Murders (1936)
* And Then There Were None (1939)
* Curtain (published posthumously in 1975)
* And many more...
* Miss Marple Series:
* The Murder at the Vicarage (1930)
* The Thirteen Problems (1932)
* A Murder is Announced (1950)
* The Body in the Library (1942)
* The Moving Finger (1942)
* A Pocket Full of Rye (1953)
* The Mirror Crack'd from Side to Side (1962)
* At Bertram's Hotel (1965)
* Nemesis (1971)
* Sleeping Murder (published posthumously in 1976)
* And many more...
* Standalone Novels:
* The Secret of Chimneys (1925)
* The Man in the Brown Suit (1924)
* The Mystery of the Blue Train (1928)
* Why Didn't They Ask Evans? (1934)
* Murder is Easy (1939)
* The Sittaford Mystery (1927)
* The Hound of Death (1933)
* The Hollow (1946)
* Dead Man's Folly (1956)
* The Pale Horse (1961)
* Passenger to Frankfurt (1972)
* And many more...
Short Story Collections:
* The Mysterious Affair at Styles (1920)
* The Poirot Stories (1923)
* The Big Four (1927)
* The Thirteen Problems (1932)
* The Hound of Death (1933)
* The Complete Poirot Short Stories (1974)
* The Complete Miss Marple Short Stories (1977)
* And many more...
Plays:
* Black Coffee (1930)
* The Mousetrap (1952)
* Witness for the Prosecution (1953)
* And many more...
This is just a small sample of the vast body of work Agatha Christie produced. To explore her complete bibliography, I recommend checking out a reputable source like Wikipedia or the Agatha Christie website.