Besides those born in 1931, I've added ten older writers.

Writers for adults (many can be seen at genarians.com):

1913 Boris Pahor (Slovene-Italian poet/novelist)

1915 Ma Shitu (Chinese politician/novelist)

1916 Geneviève Callerot (French novelist)

1917 Lise Nørgaard (Danish journalist/writer)

1918 Naomi Replansky (American poet), Henri Vernes (Belgian action/SF writer), René de Obaldia (French playwright/poet)

1919 Miroslav Zikmund (Czech travel writer)

1920 Ted Knap (American journalist), Clarissa Eden (UK memoirist and widow of PM), Roger Angell (American sports writer and New Yorker editor)

1921 Hossein Wahid Khorasani (Iranian religious writer), Hans Albert (German philosopher), Ray Lawler (Australian playwright), Edgar Morin (French philosopher)

1922 Bernard Kalb, Bernard Weisberger, Jakucho Setouchi, William Leuchtenburg, Raffaele la Capria, Angel Wagenstein, Jean Malaurie

1923 Edward Lueders, Geoffrey Ashe, Lygia Fagundes Telles, Fina Garcia Marruz, Ann Livesay Sutton, Ida Vitale, Józef Hen

1924 Robert E. Myers, Richard Rohmer, David Ferry, Herbert Gold, Gerda Klein, Edward Field, Guadalupe Rivera Marin

1925 Eugen Gomringer, Gerald Stern, Etel Adnan, Alain Touraine, Madeleine Chapsal, Albert Bandura

1926 Alfonso Sastre, Jürgen Moltmann, Ruth Minsky Sender, Arno J. Mayer, Frederick Buechner, Sami Michael, Rene Depestre, Thich Nhat Hanh, Noah Gordon, Robert Bly

1927: Martin Walser, Nayantara Sahgal, George Lamming, Midge Decter, David Ireland, Carlos Germán Belli, James Roose-Evans, Willis Barnstone

1928: Daisaku Ikeda, William Kennedy, Desmond Morris, William F. Nolan, E.D.. Hirsch, Tom Lehrer, Cynthia Ozick, Howard S. Becker, Thomas Kinsella, Michelle Perrot, Dr. Ruth Westheimer, Patrick Hemingway, Griselda Gambaro, Pavel Kohout, Jayanta Mahapatra, Christopher Davis, Noam Chomsky

1929: Amitai Etzioni, Peter Dale Scott, Alasdair MacIntyre, Len Deighton, Milan Kundera, Antonine Maillet, Harvey Cox, Harry Frankfurt, Jurgen Habermas , Arthur Frommer, Emmanuel Le Roy Ladurie, Jack Higgins, X.J. Kennedy, Yuz Aleshkovsky, Kjell Askildsen, Dr. Robert Coles, Richard Howard, Hans M. Enzensberger, Desmond O'Grady

1930: Adonis, Jennifer Johnston, Norman Podhoretz, Luce Irigaray, Gary Snyder, John Barth, Sir John Elliott, Maureen Howard, Thomas Sowell, Selma James, Johan Galtung, Stuart Briscoe, Kenneth Frampton, Christopher Nicole, Dame Edna O'Brien

1931: John McPhee, John Norman, Jorge Edwards

I've added Patricia Curtis to 1921 and Margot Webb to 1927.

Children's writers/illustrators, mostly from the "Something About the Author" encyclopedias:

1918
Joe Krush (Mary Norton's "The Borrowers" illustrator, 1952-1982)
Fern G. Brown ("Daisy and the Girl Scouts: The Story of Juliette Gordon Low," 1993)

1919
Felice Holman ("Slake's Limbo," 1974)

1920
Jean Kenward (British writer: "Ragdolly Anna" series, 1980s)
Arnold Bare (illustrator: 1944 Caldecott Honoree: Lee Kingman's "Pierre Pidgeon")
Margaret Paice (Australian writer/illustrator: "Blue Ridge Summer," 1979)
Barthe DeClements ("Nothing's Fair in Fifth Grade," 1981)
Leonard Kessler (writer/illustrator of "Mr. Pine" series, 1965-2001)

1921
Al Jaffee (MAD cartoonist)
Dorothy M. Martin (author of Protestant mysteries & "Peggy" series, 1957-1976)
Alice T. Gilbreath (1970s crafts/nature writer)
Lois Lamplugh (British novelist: "Sean's Leap," 1979)
Patricia Curtis ("Animals You Never Even Heard Of," 1997)
Belinda Hurmence ("A Girl Called Boy," 1982)
Martha Tolles ("Who's Reading Darci's Diary?" 1984)
Joyce Cooper Arkhurst (reteller of "The Adventures of Spider: West
African Folk Tales" with Jerry Pinkney, 1964)
Adrienne Richard (Newbery nominee: "Wings," 1974)

1922
Jean Bethell ("The Monkey in the Rocket," 1962)
Joan Heilbroner ("Robert, the Rose Horse," 1962)
Mildred Pitts Walter (1987 Coretta Scott King Medalist: "Justin and the Best Biscuits in the World")
Sonia Gidal (German writer: 1956-1974 "My Village" series)
Hans Peterson (Swedish author of "Magnus" series; 1976 Hans Christian Andersen Award nominee)

1923
Pieter van Raven (aka James Edward Duffy, 1990 Scott O'Dell Award winner for "A Time of Troubles")
Louise Meriwether ("Daddy Was a Numbers Runner," 1970)
John K. Tully (British author of "Starpol" series)
Josep Vallverdú (Catalan poet/novelist/playwright & 1988 HCAA nominee)
Ashley Bryan (Artist: 2-time Coretta Scott King Medalist & 2006 HCAA nominee)
William Wise ("Christopher Mouse: The Tale of a Small Traveler," 2004)
Rosamond V.P. Kaufman (adapter: "UNICEF Book of Children's Legends," 1970)
Leone Castell Anderson (novelist: "Sean's War," 1998)
Ruth Gannett (1949 Newbery Honoree: "My Father's Dragon")
Aaron Judah (British author: "God and Mr. Sourpuss," 1960)
Gloria Whelan (National Book Award winner: "Homeless Bird," 2000)
Lyuben Zidarov (Bulgarian illustrator of "Harry Potter" & HCAA nominee: 1974 & 1978)

1924
Sally Watson (historical novelist: "The Wayward Princess," 2006)
Marian Parry (illustrator: Frederick Winsor's "The Space Child's Mother Goose," 1956)
Toshiko Kanzawa (aka Toshi Furukawa, Japanese author and HCAA nominee: 2000 & 2006)
Roy A. Gallant (science writer)
Tom J. O'Sullivan (illustrator of "Kidnapped," ed. 1954)
Prudence Andrew (British author of 1960s "Ginger" series)
Gene Liberty ("The How and Why Wonder Book of Time")
Leonard Everett Fisher (Pulitzer-winning painter & historical writer
& illustrator)
Warren J. Halliburton ("Africa Today" series, 1990s)
Bernadine Cook ("The Little Fish That Got Away" with Crockett Johnson, 1956)
Jolly Roger Bradfield ("Pickle-Chiffon Pie," 1967)
Elliott Gilbert (illustrator of "The Best-Loved Doll" by Rebecca Caudill, 1962)
Eva Deutsch Costabel (Yugoslav-born painter/writer: "The Jews of New Amsterdam," 1988)
Marthe Seguin-Fontes (French writer/illustrator: "I Went Into My Garden" series, 1979)
Kirsi Kunnas (Finnish poet & 2014 HCAA nominee)

1925
Frank Graham, Jr. (nature/sports writer & Audubon Society editor)
Andre Amstutz (British illustrator of 31 Allan Ahlberg books)
Bernice Myers (writer/illustrator: "Not THIS Bear!" 1968)
Jan Truss (British-born Canadian writer: "Jasmin" 1982)
Linda Allen (British writer: "Mrs. Simkin" series, 1979-1996)
Barbara J. Brenner ("If You Lived in Williamsburg in Colonial Days" 2000)
Dr. Earl A. Grollman (grief counselor: "Straight Talk About Death for Teenagers," 1993)
Gordon Penrose (Canadian science writer: "Dr. Zed" series)
Laurent de Brunhoff (French writer/illustrator: "Babar's Fair")
Ronni Solbert (illustrator of "The Pushcart War" by Jean Merrill, 1964)
Edward Ormondroyd ("David and the Phoenix," 1957)
Wilanne Schneider Belden (1980s fantasy novelist: "Mind-Call" trilogy)
Domenico Volpi (Italian author and HCAA nominee, 1974)

1926
Ina Friedman ("How My Parents Learned to Eat," 1984)
Alain Trez (French cartoonist/illustrator)
Carla Stevens (aka Carla Stevens Bigelow: "Rabbit & Skunk and the Scary Rock," 1976)
Sandy Kossin (illustrator & movie poster designer for "Becket")
George Booth ("New Yorker" cartoonist)
Margaret Storey (British fantasy & mystery author: "Timothy & Two Witches," 1966)
Patricia Coombs ("Dorrie" witch series, 1962-1992)
George Ford (Illustrator & 1973 Coretta Scott King Medalist: "Ray Charles" by Sharon B. Mathis)
Alfred Slote (aka A. H. Garnet, baseball and sci-fi novelist)
Hilda Perera (Cuban-born YA novelist & Nobel Prize nominee)
Darwin McBeth Walton ("Kwanzaa: A World of Holidays," 1998)
Tadashi Matsui (Japanese publisher/reteller)
Miriam Cohen ("Will I Have a Friend?" 1967)
Muriel Batherman ("Before Columbus," 1981)
Hilary Knight (illustrator: Kay Thompson's "Eloise")
Herma Werner (romance/mystery/adventure writer, aka Eve Cowen & Eve Gladstone, 1978-1994)
Joan Solomon (South African-born British writer: "Everybody's Hair," 1988)
Dorothy B. Francis (romance/mystery/Western novelist)
Harriette Abels (sci-fi/romance/mystery novelist)
Marjorie-Ann Watts (British illustrator of Catherine Storr's "Polly and the Wolf" series)

1927
Mary Chalmers (illustrator: "The Secret Language" by Ursula Nordstrom, 1960)
Ruth Lercher Bornstein ("The Summer Everything Changed," 2012)
Robert Andrew Parker (painter/illustrator: "Who Was Albert Einstein?" by Jess Brallier, 2002)
M.E. Kerr (YA novelist: "Dinky Hocker Shoots Smack!" 1972)
Ancka Gošnik Godec (Slovene illustrator & 2010 HCAA nominee)
Richard B. Lyttle (artist, reporter, biographer)
Carol Lerner (Botanical writer: "Plants that Make You Sniffle & Sneeze," 1993)
Shirley Hughes (British illustrator & 1998 HCAA nominee)
Niels Jensen (Danish author: "Days of Courage," 1972)
George Sullivan (sports/biographies/nonfiction writer)
Melvin Berger (author of 200 science/nonfiction books)
Mort Künstler (MAD cartoonist, illustrator, & historical painter)
Margot Webb (German-born writer: "Too Young To Die: The Story of José," 2003)
Dorothy Levenson (Australian-born writer: "The Magic Carousel," 1967)
Betty Levin (fantasy/mystery/adventure writer)
Barbara Klimowicz ("When Shoes Eat Socks," 1971)
Christine King Farris (memoirist: "My Brother Martin: A Sister Remembers Growing Up with the Rev. Dr. Martin Luther King, Jr.," 2003)
Richard Brightfield (writer for "Choose Your Own Adventure" series)
Don Madden (writer/illustrator: "The Wartville Wizard," 1986)
Julian F. Thompson (YA novelist: "A Band of Angels," 1986)
Marlenka Stupica (Slovene illustrator & 2-time HCAA nominee: 1974, 1996)
Elizabeth Fitzgerald Howard (2001 Coretta Scott King Honoree: "Virgie Goes to School with Us Boys")

1928
Barbara M. Walker ("The Little House Cookbook," 1979)
Mino Milani (Italian adventure novelist & HCAA nominee, 1962 & 2008)
Marilyn Gould (Writer on skateboarding and "Golden Daffodils," 1985)
Betty Fraser (Illustrator: Hoberman's "The Llama Who Had No Pajama")
Lore Segal (Austrian-born writer & translator: Grimm's "The Juniper Tree," illustrated by Maurice Sendak)
Harvey Dinnerstein (Artist: "At the Back of the North Wind" by George MacDonald, ed. 1964)
Tom Hamil (Painter/illustrator: "Calvin and the Cub Scouts" by Patricia Miles Martin, 1964)
Mary Lystad ("James the Jaguar," 1972)
Frank Newfeld (Czech-born Canadian designer/illustrator: "Alligator Pie" by Dennis Lee, 1974)
Jacqueline Dougan Jackson (writer/poet/illustrator: "Turn Not Pale, Beloved Snail," 1974)
Ellen Viereck (Painter/illustrator, "The Summer I Was Lost" by Paul Viereck, 1965)
V. Gilbert Beers (Baptist writer: "The Early Readers Bible," 1991)
Shirley Rousseau Murphy (Fantasy/mystery writer: "Joe Grey" cat series, 1996-2010)
Luis Camps (French illustrator: "The Smashers" 1970s series by Alain Gree)
Arnold Dobrin (Writer/illustrator, "Scat!" 1970)
Janice May Udry (1957 Caldecott Medalist: "A Tree is Nice," with Marc Simont)
Virginia Lee (aka Virginia L. Ewbank, Virginia Ewbank Hendricks, and Virginia L Hendricks,"The Magic Moth," 1972)
Nan Holcomb (author of elementary stories about handicapped children; real name, Norma McPhee)
James Lincoln Collier (1975 Newbery Honoree & National Book Award nominee: "My Brother Sam is Dead")
Elizabeth van Steenwyk (writer of historical novels, horse novels, & mysteries)
Patricia Hubbell (Poet: "Trucks Whizz! Zoom! Rumble!" 2003)
Jane Gardam (UK writer & Carnegie nominee: "The Hollow Land," 1981)
Kveta Pacovska (Czech illustrator & 1992 HCAA Medalist)
Phyllis Hollander (Co-author: "Amazing But True Sports Stories," 1986)
Eva Hulsmann (French/German/Italian nature illustrator)
Shulamith L. Oppenheim ("The Sea King" with Jane Yolen, 2003)
Esther L. Nelson ("Dancing Games for Children of All Ages," 1973)
Judith Crabtree (Australian fantasy novelist/illustrator: "Song at the Gate," 1987)
Sidney Offit ("The Adventures of Homer Fink," 1966)
Earle Rice Jr. (YA war history writer)
Toby Talbot ("Dear Greta Garbo," 1977)
Diane Sherman (aka Diane Sherman-Levine, medium, healer, & preschool writer: "Little Skater," 1959)
Eve Bunting (Northern Ireland-born writer of 200 books & Edgar winner)
Alice M. Fleming (nonfiction writer: "Martin Luther King: A Dream of Hope," 2008)
Carolee Wells Henney ("The Cat in the Tower," 2017)
Lilo Fromm (German illustrator & HCAA nominee: 1968, 1974, 1982)

1929
Jules Feiffer (cartoonist: "The Phantom Tollbooth" by Norton Juster, 1961)
Walter Lorraine (editor/illustrator: "McBroom" series by Sid Fleischman, 1960s-1980s)
Iona MacGregor (British historical novelist & author of "Death Wore a Diadem")
Doris Orgel (Austrian-born novelist/translator: "The Princess and the God," 1996)
Arnold Roth (cartoonist: "Grimms' Fairy Tales," 1966)
Ruth Belov Gross ("If You Grew Up With George Washington," 1982)
Paul Coker (MAD cartoonist)
Joan M. Lexau ("Striped Ice Cream!" 1968)
Hilde Heyduck-Huth (German writer/illustrator: "The Three Birds," 1966)
Edward Sorel (political cartoonist: "The Pirates of Penzance," adapted by Ward Botsford, 1981)
Jacqueline L. Harris ("The Tuskegee Airmen: Black Heroes of World War II," 1996)
Jane Wooster Scott (Illustrator & American folk art painter)
Eloise Greenfield (1978 Coretta Scott King Award winner: "Africa Dream")
Lensey Namioka (nee Lensey Chao, Chinese-born writer: "Ties That Bind, Ties That Break," 1999)
Don Almquist (Painter/illustrator of Catherine Woolley's "Libby Shadows a Lady," 1974)
Christine San Jose (British-born senior editor of "Highlights" magazine)
Norma J. Livo ("Moon Cakes to Maize: Delicious World Folktales," 1999)
Lynne Reid Banks (British author: "The Indian in the Cupboard," 1980)
K.M. Peyton (1969 Carnegie Medalist: "The Edge of the Cloud")
Norman L. Macht (Sports biographer)
Peter F. Neumeyer (German-born writer: "The Annotated Charlotte's Web," 1994)
Wendy Pfeffer ("Let's Read and Find Out" science series)
Graham Oakley (British writer/illustrator of "Church Mice" series & Kate Greenaway nominee: 1976, 1982)
Sesyle Joslin (1959 Caldecott Honoree: "What Do You Say, Dear?" with Maurice Sendak)
Aliki Brandenberg (aka Aliki, writer/illustrator: "A Medieval Feast," 1983)
Elizabeth Hall ("Thunder Rolling in the Mountains," 1992, with Scott O'Dell)
Patty Wolcott ("The Marvelous Mud Washing Machine," 1974)
Gioia Fiammenghi (Illustrator: Thomas Rockwell's "How to Fight a Girl," 1987)
Dorothy W. Robinson (1975 Coretta Scott King Medalist: "The Legend of Africania")
Marjorie Ann Waybill ("Chinese Eyes," 1974)
Peter R. Limburg (Science writer of "What's Behind the Word" series)
Lael Littke (YA mystery/romance/horror novelist: "Prom Dress," 1989)
Martha E. Rhynes (Biographer: "Ralph Ellison: Author of Invisible Man," 2006)
Brian Earnshaw (Welsh author: "Dragonfall 5" series, 1970s)
Hong Seong-Chan (aka Hong Sungchan, S. Korean illustrator & HCAA nominee, 2012)

1930:
Eric Houghton (British writer: "Walter's Magic Wand,"1989)
Monica Gunning (Jamaican-born writer: "A Shelter in Our Car," 2004)
Shirley Jordan (history writer: "World War II," 1998)
Barbara Shook Hazen ("The Knight Who Was Afraid of the Dark," 1989)
Bruce Roberts (photographer & co-author of books on ghosts)
Ilon Wikland (Swedish illustrator & HCAA nominee, 1998)
Josef Wilkon (Polish illustrator & HCAA nominee: 1976, 1980, 2000, 2004)
Mary Razzell (Canadian YA novelist: "Snow Apples," 1984)
Kathlyn Gay (author of "Voices from the Past" war series, 1990s)
David Gentleman (British artist of Shakespeare, Keats, & Kipling)
Jeanne Williams (YA novelist & romance/Western writer)
Janice Shefelman (historical writer of "Texas Trilogy," 1980s)
Joan Hewett (nonfiction writer: "Baby Animals" series, 2001-2002)
Nancy Polette ("The Thinker's Mother Goose," 1983)
Jenny Seed (South African historical novelist)
Aranka Siegal (Czech/Hungarian-born writer & 1982 Newbery Honoree: "Upon the Head of the Goat: A Childhood in Hungary 1939-1944")
Helen J. Borten (journalist & illustrator: "Do You See What I See?," 1959)
Len Lamensdorf (sci-fi novelist: "The Crouching Dragon," 1999)
Lois Sabin (writer on sports/bios/history/nature/mystery)
Kay Life (aka Kay Guinn-Life, illustrator of Beverly Cleary's "Muggie Maggie")
Don Berliner (1980s writer on aviation)
Gloria Skurzynski (mystery/SF/historical novelist)
Charlotte Pomerantz (1975 Jane Addams Medalist: "The Princess & the Admiral")
Jean Russell Larson ("The Fish Bride and Other Gypsy Tales," 1999)
Suzanne Tate (Biologist and 1990s writer on marine life)
Mary Dodson Wade (Biographer: "Joan Lowery Nixon: Mystery Writer," 2004)
Necia H. Apfel (Astronomer)
Inger Sandberg (Swedish author of "Little Anna" series, 1964-1982)
Mary Ann Hoberman (Poet: "The Llama Who Had No Pajama," 1998)
Reynold Ruffins (Illustrator & 1997 Coretta Scott King Honoree: "Running the Road to ABC" by Denize Lauture)
Kenneth Thomasma (author of "American Indian Children" series, 1983-2018)
Byron Barton (Preschool writer/illustrator: "Where's Al?," 1972)
Robert Carl Cohen ("The Color of Man," 1968)
Connie Brummell Crook (Canadian historical novelist: "Nellie's Quest," 1998)
Faith Ringgold (Artist, 1992 Caldecott Honoree and Coretta Scott King Medalist: "Tar Beach")
Carl Sommer (Educator: "Another Sommer-Time Story" series, 2000s )
Harriet Sirof (YA writer: "The Real World," 1985)
Caroline Crane (1960s YA writer & 1980s mystery writer)
Tonke Dragt (Dutch SF/fantasy author & HCAA nominee, 2012)
Bernadette M. Snyder (Catholic humorist)
Mary Blair Immel ("Captured!: A Boy Trapped in the Civil War," 2005)
Reiner Zimnik (Polish-born German writer/illustrator)
Natalie S. Bober (YA biographer: "Abigail Adams: Witness to a Revolution," 1995)

1931
Wick Downing ("The Trials of Katie Hope," 2008)
Ann Elwood ("The Macmillan Book of Fascinating Facts," 1989)
Joy Hakim (series author: "A History of U.S.," 1993-2003)
John C. Branfield (Carnegie nominee: "The Fox in Winter," 1980)
Judith Viorst ("Alexander and the Terrible, Horrible, No Good, Very Bad Day," 1972)
Dorothy Joan Harris (Canadian writer: "The House Mouse" with Barbara Cooney, 1973)
Edward Packard ("Choose Your Own Adventure" series)
Uri Orlev (Polish-born Israeli author & 1996 HCAA Medalist)
Ruth Rocha (Brazilian writer & HCAA nominee, 2002)
Mort Gerberg (cartoonist: "More Spaghetti, I Say!" by Rita Golden Gelman, 1977)
Janosch (aka Horst Eckert, German illustrator & HCAA nominee: 1972, 1976, 1978, 1980)
Vivian Dubrovin ("Tradin' Tales With Grandpa," 2000)
Schlaepfer (Writer on animals, 1992-2005)
Lilian Obligado (Argentine artist: "The Golden Egg Book" ed. 1962, by Margaret Wise Brown)
Jacqueline Stem ("The Secret Of The Dragonfly Pin," 2006)
Middy Thomas (artist: Lois Lowry's recent "Gooney Bird" series)
Constance Levy (Missouri poet: "The Story of the Red Rubber Ball," 2004)
Laszlo Acs (Hungarian-born British illustrator: "The Exeter Blitz" by David Rees, 1978)
Irene Watts (German-born Canadian playwright: "Goodbye Marianne," 1998)
Ivy Ruckman ("The Night of the Twisters," 1984)
Frances Zweifel (science illustrator: 1990s "Simple Experiments" series)
Griselda Gifford (British author: "The Story of Ranald," 1968)
Hal Higdon ("The Horse That Played Center Field," 1969)
Alexander Traugot (Russian artist & HCAA nominee, 2006)
Ellen Blance (British-born writer of "Monster" series, 1970s-1980s, with Quentin Blake)

Schlaepfer (Writer on animals, 1992-2005)

Oops - that should be GLORIA Schlaepfer.