These are on my (around) 10yo list:
Little Women
Little Men
The Door in the Wall
Sounder
The True Confessions of Charlotte Doyle
Crispin At the Edge of the World (Trilogy)
Peter Pan
The Book of Virtues
Hostage Lands
Caddie Woodlawn
Pilgrim’s Progress**
Fine Print: A Story about Johann Gutenberg
The Incredible Journey
The Strange Intruder
Catherine, Called Birdy
The Magna Charta
Robinson Crusoe
Shadrach
Children’s Stories from Dickens
Hans Brinker and the Silver Skates
The 21 Balloons
Johnny Tremain
The Story of Rolf and the Viking Bow
Cheaper By the Dozen
Old Yeller
Adam of the Road
In Freedom’s Cause: The Story of Wallace & Bruce
Ten Boys Who Made a Difference
The Queen’s Smuggler – William Tyndale
The Betrayer’s Fortune
Traitor in the Tower
Hidden Treasure of Glaston
The Jungle Books
The Second Mrs. Gioconda
Tales from Shakespeare
The Tinker’s Daughter
The Chronicles of Narnia
Call of the Wild
White Fang
Hiawatha
The Puppeteer’s Apprentice
Castle, Cathedral
Masada
Anne of Green Gables (Series)
Little Britches Series
Five Children and It
Polycarp: The Crown of Fire
Joan of Arc
Mrs. Frisby and the Rats of Nimh
The Black Pearl
The Island of the Blue Dolphins
Bruchko
The Master Puppeteer
Red Falcons of Tremoine
Beorn the Proud
Pollyanna
Otto of the Silver Hand
The Merry Adventures of Robin Hood
Red Hugh, Prince of Donegal
Bambi
The Good Master
The White Stag
Black Beauty
A Comedy of Errors**
In His Steps
Five Little Peppers and How They Grew
The Witch of Blackbird Pond
The Bronze Bow
Tanglewood’s Secret (All)
Kidnapped
The Mysterious Benedict Society
The Silver Branch
The Eagle of the Ninth
Gulliver’s Travels
All-of-a-Kind Family
Morning Star of the Reformation
Mary Poppins
Tirzah
Twenty Thousand Leagues Under the Sea
The Man Who Laid the Egg
The Begger’s Bible
Thunderstorm in Church
The Bible Smuggler
Medallion
King Arthur and His Knights
Listening for Lions
The Life & Times of Charlemagne
Son of Charlemagne
If All the Swords in England
Augustine Came to Kent
Forbidden Gates
Detectives in Togas
Swiss Family Robinson
When I compiled this, we were in the Middle Ages, so some of these ‘lean’ thataway. I need to update it to include other time periods – but maybe you’ll get some ideas!