Recently Tiffany Obeng, the author of "I Have Ten Toes," recommended two books to me. One of them is a fun book called, "Kai, The Missionary Sea Turtle."
My go-to children’s missions book is still "Hudson on A Mission" which follows the journey of a family who shares the message of Jesus Christ, Lord and Savior, with a village.
I also recommend "The Hidden Village" from BJU Press. It's an engaging story.
PS Tiffany Obeng also suggested "Written In The Stars For You," but I haven't read it. It's by Tyranika Abrams.