I happened upon Zonderkidz readers when I was looking for good character-building readers for home school. These are my favorites:
Otter & Owl Series by Crystal Bowman (Same author who wrote the One Year Devotions for Preschoolers)
Otter & Owl and the Big Hike about helping others. Otter and Owl and the Big Ah-choo! is about the importance of friendship. Otter and Owl Set Sail is about learning that we don't have the power to do all things, but we can call on the one who does. Otter and Owl Say I'm Sorry is about friendship and forgiveness.
Mad Maddie Maxwell by Stacie K.B. Maslyn is one of my very favorite readers. It is a little easier to read than the Otter and Owl series, so my son chose it to read a lot. Maddie's jump rope is missing. When she doesn't find it in all the usual places, she gets angry and blames each of her siblings until her older sister finds it under Maddie's own bed. Maddie's sister prays with Maddie and Maddie learns the importance of forgiveness as each of her siblings chooses to forgive her.
Little David Series by Crystal Bowman are stories about King David from the Bible
Little David's Brave Day This story is about bullies and bravery. Little David and his brothers are mice and Goliath is a big cat who keeps bullying them. Little David's brothers are scared and hide inside, but Little David chases Goliath off with a watering hose. I love how the author portrays this Biblical story. Also in this series are: Little David's Big Heart, Little David Sings for the King, Little David and His Best Friend.