I needed a list sorted by characters; since I couldn't find one I liked, I made my own. Includes both UK and US titles.
Hercule Poirot:
The Mysterious Affair at Styles
(1921)
The Murder on the Links (1923)
Poirot Investigates* (1924)
The Murder of Roger Ackroyd (1926)
The Big Four (1927)
The Mystery of the Blue Train (1928)
Peril at End House (1932)
Lord Edgeware Dies/Thirteen at Dinner (1933)
Murder on the Orient Express/Murder in the Calais Coach (1934)
Three Act Tragedy/Murder in Three Acts (1935)
Death in the Clouds/Death in the Air (1935)
The A.B.C. Murders (1936)
Murder in Mesopotamia (1936)
Cards on the Table (1936)
Dumb Witness/Poirot Loses a Client (1937)
Death on the Nile (1937)
Murder in the Mews/Dead Man's Mirror* (1937)
Appointment with Death (1938)
Hercule Poirot's Christmas/Murder for Christmas (1938)
The Regatta Mystery and Other Stories* (1939)
Sad Cypress (1940)
One, Two, Buckle My Shoe/The Patriotic Murders (1940)
Evil Under the Sun (1941)
Five Little Pigs/Murder in Retrospect (1942)
The Hollow (1946)
The Labours of Hercules/The Labors of Hercules* (1947)
Taken at the Flood/There is a Tide... (1948)
Three Blind Mice and Other Stories* (1950)
The Under Dog and Other Stories* (1951)
Mrs. McGinty's Dead (1952)
After the Funeral/Funerals are Fatal (1953)
Hickory Dickory Dock (1955)
Dead Man's Folly (1956)
Cat Among the Pigeons (1959)
The Adventure of the Christmas Pudding* (1960)
The Clocks (1963)
Third Girl (1966)
Hallowe'en Party (1969)
Elephants Can Remember (1972)
Poirot's Early Cases (1974)
Curtain (1975)
Tommy and Tuppence:
The Secret Adversary (1922)
Partners in Crime* (1929)
N or M? (1941)
By the Pricking of My Thumbs (1968)
Postern of Fate (1973)
Colonel Race:
The Man in the Brown Suit (1924)
Cards on the Table (1936)
Death on the Nile (1937)
Sparkling Cyanide/Remembered Death (1945)
Superintendent Battle:
The Secret of Chimneys (1925)
The Seven Dials Mystery (1929)
Cards on the Table (1936)
Murder is Easy/Easy to Kill (1939)
Towards Zero (1944)
Miss Marple:
The Murder at the Vicarage
(1930)
The Thirteen Problems/The Tuesday Club Murders* (1932)
The Regatta Mystery and Other Stories* (1939)
The Body in the Library (1942)
The Moving Finger (1943)
A Murder is Announced (1950)
Three Blind Mice and Other Stories* (1950)
They Do It with Mirrors/Murder with Mirrors (1952)
A Pocketful of Rye (1953)
4.50 from Paddington/What Mrs.
McGillicuddy Saw (1957)
The Adventure of the Christmas
Pudding* (1960)
The Mirror Crack'd from Side to Side/The
Mirror Crack'd (1962)
A Caribbean Mystery (1964)
At
Bertram's Hotel (1965)
Nemesis (1971)
Sleeping
Murder (1976)
Ariadne Oliver appears in:
Parker Pyne Investigates/Mr. Parker Pyne, Detective* (1934)
(cameo appearance)
Cards
on the Table (1936)
Mrs. McGinty's Dead (1952)
Dead
Man's Folly (1956)
The Pale Horse (1961)
Third
Girl (1966)
Hallowe'en Party (1969)
Elephants Can
Remember (1972)
Standalone Novels or Collections and Mixed Collections:
The Mysterious Mr. Quin* (1930)
The Floating Admiral (1931)
The Sittaford Mystery/The Murder at Hazelmoor (1931)
The Hound of Death* (1933)
Why Didn't They Ask Evans?/The Boomerang Clue (1934)
Parker Pyne Investigates/Mr. Parker Pyne, Detective* (1934)
The Listerdale Mystery* (1934)
Ten Little Indians/And Then There Were None (1939)
The Regatta Mystery and Other Stories* (1939)
Death Comes as the End (1945)
Crooked House (1949)
Three Blind Mice and Other Stories* (1950)
They Came to Baghdad (1951)
Destination Unknown/So Many Steps to Death (1954)
Ordeal by Innocence (1958)
The Adventure of the Christmas Pudding* (1960)
The Pale Horse (1961)
Endless Night (1967)
Passenger to Frankfurt (1970)
As Mary Westmacott:
Giant's Bread (1930)
Unfinished Portrait (1934)
Absent in Spring (1944)
The Rose and the Yew Tree (1948)
A Daughter's a Daughter (1952)
The Burden (1956)
___________
*indicates short story collection
