ISFDB lumps all short fiction into the same list. All I've done here is take the ISFDB data (http://www.isfdb.org/cgi-bin/ea.cgi?36) and reproduce it with the stories sorted into the three standard short fiction categories of Short, Novelette, and Novella. I'd be interested to see word counts for the novels. I don't think that many of them are much longer than long novellas.
191 Shorts
The Wagons (1959)
The Ugly Sea (1960)
Saturday You Die (1960)
Adam Had Three Brothers (1960)
Day of the Glacier (1960)
Other Side of the Moon (1960)
Long Teeth (1960)
Beautiful Dreamer (1960)
McGonigal's Worm (1960)
Try to Remember (1960)
The Polite People of Pudibundia (1961)
In the Garden (1961)
All the People (1961)
The Weirdest World (1961)
Aloys (1961)
Rainbird (1961)
Seven-Day Terror (1962)
Dream (1962) also appeared as:
Variant Title: Dreamworld (1962)
Sodom and Gomorrah, Texas (1962)
The Transcendent Tigers (1964)
Name of the Snake (1964)
What's the Name of That Town? (1964)
Mad Man (1964)
Pig in a Pokey (1964)
The Man with the Speckled Eyes (1964)
Slow Tuesday Night (1965)
Guesting Time (1965)
In Our Block (1965)
Hog-Belly Honey (1965)
Nine Hundred Grandmothers (1966)
Golden Trabant (1966)
Among the Hairy Earthmen (1966)
Narrow Valley (1966)
Primary Education of the Camiroi (1966) also appeared as:
Variant Title: The Primary Education of the Camiroi (1966)
The Man Who Never Was (1967)
The Hole on the Corner (1967)
Thus We Frustrate Charlemagne (1967)
Ginny Wrapped in the Sun (1967)
Land of the Great Horses (1967)
Camels and Dromedaries, Clem (1967)
Polity and Custom of the Camiroi (1967)
The Ultimate Creature (1967)
One at a Time (1968)
Maybe Jones and the City (1968)
How They Gave It Back (1968)
McGruder's Marvels (1968)
This Grand Carcass (1968) also appeared as:
Variant Title: This Grand Carcass Yet (1968)
Cliffs That Laughed (1969)
Configuration of the North Shore (1969)
Entire and Perfect Chrysolite (1970)
Hands of the Man (1970)
Ride a Tin Can (1970)
Old Foot Forgot (1970)
About a Secret Crocodile (1970)
The Cliff Climbers (1970)
Condillac's Statue, or Wrens in His Head (1970)
Interurban Queen (1970)
All Pieces of a River Shore (1970)
Been a Long, Long Time (1970)
Sky (1971)
Nor Limestone Islands (1971)
When All the Lands Pour Out Again (1971)
Groaning Hinges of the World (1971)
The Man Underneath (1971)
Enfant Terrible (1971)
All But the Words (1971)
Boomer Flats (1971)
Bubbles When They Burst (1971)
Eurema's Dam (1972)
Once on Aranea (1972)
A Special Condition in Summit City (1972)
Rang Dang Kaloof (1972)
Dorg (1972)
In Outraged Stone (1973)
The Ungodly Mice of Doctor Drakos (1973)
The Wooly World of Barnaby Sheen (1973)
Four Sides of Infinity (1973)
Barnaby's Clock (1973)
Symposium (1973)
The Two-Headed Lion of Cris Benedetti (1973)
The Hellaceous Rocket of Harry O'Donovan (1973)
Rogue Raft (1973)
Parthen (1973)
Ghost in the Corn Crib (1973)
The World as Will and Wallpaper (1973)
Seven Story Dream (1973)
Days of Grass, Days of Straw (1973)
By the Seashore (1973)
And Name My Name (1974)
The Most Forgetable Story in the World (1974)
The Man with the Aura (1974) also appeared as:
Variant Title: Tom O'Shanty's Aura (1974)
And Mad Undancing Bears (1974)
And Read the Flesh Between the Lines (1974)
Royal Licorice (1974)
Endangered Species (1974)
For All Poor Folks at Picketwire (1975)
Great Day in the Morning (1975)
Old Halloweens on the Guna Slopes (1975)
The Skinny People of Leptophlebo Street (1975)
Fog in My Throat (1976)
Cabrito (1976)
Horns on Their Heads (1976)
Funnyfingers (1976)
Love Affair With Ten Thousand Springs (1976)
The Hand with One Hundred Fingers (1976)
Oh Tell Me Will It Freeze Tonight (1976)
Assault on Fat Mountain (1976)
Puddle on the Floor (1976)
Berryhill (1976)
Oh, Those Trepidatious Eyes! (1977)
Brain Fever Season (1977)
Thou Whited Wall (1977)
Fall of Pebble-Stones (1977)
Bequest of Wings (1978)
Bright Coins in Never-Ending Stream (1978)
Splinters (1978)
Bright Flightways (1978)
Oh Tell Me It Will Freeze Tonight (1979)
Rainy Day in Halicarnasses (1979)
Almost Perfect (1980)
Phoenic' (1980) also appeared as:
Variant Title: Phoenic (1980)
Lord Torpedo, Lord Gyroscope (1980)
And All the Skies Are Full of Fish (1980)
The Only Tune That He Could Play (1980)
Crocodile (1980)
New People (1981)
In Deepest Glass (1981)
You Can't Go Back (1981)
Golden Gate (1982)
Six Leagues From Lop (1982)
Great Tom Fool or The Conundrum of the Calais Customhouse Coffers (1982)
Thieving Bear Planet (1982)
Square and Above Board (1982)
Ifrit (1982)
Calamities of the Last Pauper (1982) also appeared as:
Variant Title: Calamities of Last Pauper (1982)
One-Eyed Mocking-Bird (1982)
Marsilia V (1982)
Make Sure the Eyes Are Big Enough (1982)
Tongues of the Matagorda (1982)
This Boding Itch (1982)
Company in the Wings (1983)
What Big Tears the Dinosaur's (1983)
Unique Adventure Gone (1983)
Snake in His Bosom (1983)
Posterior Analytics (1983)
Pleasures and Palaces (1983)
Jack Bang's Eyes (1983)
Haruspex (1983)
Heart of Stone, Dear (1983)
The End of Outward (1983)
And You Did Not Wail (1983)
Bird-Master (1983)
Faith Sufficient (1983)
In the Turpentine Trees (1983)
The Last Astronomer (1983)
Pine Castle (1983)
Two For Four Ninety-Five (1984)
Of Laughter and the Love of Friends (1984)
The Effigy Histories (1984)
I'll See It Done and Then I'll Die (1984)
The Ninety-Ninth Cubicle (1984) also appeared as:
Variant Title: 99th Cubicle (1984)
And Some in Velvet Gowns (1984)
The Doggone Highly Scientific Door (1984)
Oh Whatta You Do When the Well Runs Dry? (1984)
The Man Who Made Models (1984)
John Salt (1985)
All Hollow Though You Be (1985)
Ewe Lamb (1985)
Slippery (1985)
Magazine Section (1985)
Junkyard Thoughts (1986)
Inventions Bright and New (1986)
Something Rich and Strange (1986)
Along the San Pennatus Fault (1986)
Gray Ghost: A Reminiscence (1987)
The Story of Little Briar-Rose, A Scholarly Study (1988)
Task Force Fifty-Eight and One Half (1988)
Rain Mountain (1988)
Rainy Day in Halicarnassus (1988)
Promontory Goats (1988)
Le Hot Sport (1988)
The Man Who Lost His Magic (1989)
Holy Woman (1990)
Maleficent Morning (1990)
Apocryphal Passage of the Last Night of Count Finnegan On Galveston Island (1990)
The Casey Machine (1990)
Buckets Full of Brains (1991)
Anamnesis (1992)
I Don't Care Who Keeps the Cows (1994)
Goldfish (1996)
There'll Always Be Another Me (2003)
33 Novelettes
Through Other Eyes (1960)
The Six Fingers of Time (1960)
Snuffles (1960)
The Pani Planet (1965)
The All-At-Once Man (1970)
Frog on the Mountain (1970)
Continued on Next Rock (1970)
Encased in Ancient Rind (1971) also appeared as:
Variant Title: Incased in Ancient Rind (1971)
Ishmael Into the Barrens (1971)
World Abounding (1971)
And Walk Now Gently Through the Fire (1972)
Scorner's Seat (1973)
Mud Violet (1973)
Flaming Ducks and Giant Bread (1974)
Mr. Hamadryad (1974)
Animal Fair (1974)
Rivers of Damascus (1974)
Or Little Ducks Each Day (1975)
Heart Grow Fonder (1975)
Three Shadows of the Wolf (1975)
Smoe and the Implicit Clay (1976)
Selenium Ghosts of the Eighteen Seventies (1978)
Quiz Ship Loose (1978)
The Man Who Walked Through Cracks (1978)
St. Poleander's Eve (1979)
The Funny Face Murders (1980)
The Forty-Seventh Island (1980)
Bank and Shoal of Time (1981)
Flaming-Arrow (1985)
Episodes of the Argo (1990)
Hound Dog's Ear (1991)
Happening in Chosky Bottoms (1995)
The Emperor's Shoestrings (1997)
1 Novella
From the Thunder Colt's Mouth (1975)