Start with high-confidence christian people & places books, then narrow by subgenre or adjacent topics.
My Little Golden Book About God
Jane Werner Watson
How High Is Heaven?
Linsey Davis
Tomie Depaola's Book of Bible Stories
Tomie dePaola
A Travel Guide to Heaven for Kids
Anthony DeStefano
Every Nation
Sarah Nunnally
Every Neighbor
Francis Woke Up Early
Josephine Nobisso
The Night Before My First Communion
Natasha Wing, Amy Wummer
Good Night Baby Jesus
Adam Gamble
Jesus Loves Me (little Sunbeams)
Ginger Swift
Good Samaritan
Russell Punter