While not an exhaustive list by any measure, these are some of my favorite children books with libertarian themes. I have only included books that I have read.
Please add any recommendations to the comments section.
The Three Little Pigs
The Ant and the Grasshopper
The Emperor's New Clothes
Yertle the Turtle by Dr. Seuss
Thidwick the Big-hearted Moose by Dr. Seuss
Grades 1 – 3
They can read the above books or read to them the Little House and Narnia books.
An Island Called Liberty by Joseph Specht
Grades 4 – 5
Little House Series by Laura Ingalls Wilder
Little House: The Rose Years by Roger Lea MacBride
The Chronicles of Narnia by C. S. Lewis
Grades 6 – 8
The Shadow Children Series by Margaret Peterson Haddix (okay for some 4th and 5th graders)
Atlas Shrugged by Ayn Rand
1984 and Animal Farm by George Orwell