The ABCs of God's Attributes by Tiny Theologians is a fun way to introduce kids to the unchanging character of God. This resource includes 26 "flash cards" (one for each letter of the alphabet). Each card reveals one of God's attributes - along with an explanation and a scripture.
We love these because they are so accessible - all it takes is 5 minutes at the dinner table, at bedtime, in the car, etc. Also, it teaches our little ones about who God is and always will be.