Here are some resources that I have come across for teaching kids theology and Bible stories.
Theology for kids:
Haven’t read yet, but have read other stuff by Susan Hunt; basically this book teaches kids the catechism: Big Truths for Little Kids by Susan and Richie Hunt (It’s recommended for ages 4-8 years, but could possibly do sooner)
It’s recommended for ages 6-11 years but could potentially start it earlier than that.
There is also a CD by Sovereign Grace Music that puts theology to music. Called The Ology: Ancient Truths Ever New.
Big Truths for Young Hearts by Bruce Ware (It’s recommended for ages 6-14. Chapters are pretty short, so could be used as a family devotional.)
Commentary for children:
Recommended for age 3 and up. I would say if read with younger children to edit it. Also no pictures so might be harder to engage with younger. Could be used as family devotional. You could always go through it with your spouse and then determine when it would work for your own kids. I would say for upper elementary. The series also has Exodus, Leviticus, Numbers, and Deuteronomy but I haven’t read any of those yet.
Bible stories for kids:
Arch Books series
I have not read all these (they have a ton of them) but was shown them by one of the ladies at our church and they look like good options for teaching Bible stories to kids. Here’s one of them: Jesus Teaches Not to Worry. I plan to use the one on Ruth for the childcare kids I’m watching on Thursdays.