Awana Clubs, a midweek Bible Club for children, has been around for a lot of years and has effectively disciple millions of children. Recently they joined with Crossway to offer a English Standard Translation version of Awana. You can learn more about Awana here.
Preschoolers (Age 3-5)
Recently I was asked to review Awana materials and received a box of supplies for Cubbies (preschool). I loved it. It was easy to use and had lots of colorful resources including name badges, t-shirts, puppets, stuffed animals, and a storybook for parents to use at home. But the most important feature is it teaches preschoolers the Word of God at an age appropriate level. I highly recommend it.