Here are a few that we have found helpful:
1) Table Talk by Alison Mitchell
These provide a short Bible study - a few questions to discuss about part of the Bible, a chance to think about how the passage might apply, and some ideas for prayer. It pairs up with XTB Bible notes, so a child could go on to do further study on the same passage. We found that these notes were particularly useful when our children were aged about 4-8.
2) The Big Picture Family Devotional by David R. Helm
These notes take you through the whole Bible story, with a memory verse to learn for each week as you trace the story of salvation together. We took our time with these notes, and although we are not word perfect on all the verses, it is encouraging to see just how much has stuck in the children's minds. It is a good way to get a sense of the shape of the Bible, and to commit some scripture to memory. These notes are probably better suited to slightly older children (6 +).
3) Wise Up by Marty Machowski
These notes are centred on the book of Proverbs, although certain themes are explored in other parts of the Bible too. Each day focuses on a particular Bible passage, has some reflections to read out loud, and some questions for discussion. It was good to have some thoughtfully applied Bible devotions for us to use in discussion with our children. Again, these are probably better for slightly older children (6+).
4) Awesome Cutlery Family Devotionals
Our children have enjoyed listening to our Awesome Cutlery CD - full of Bible truths. This set of family devotionals picks up on some key gospel ideas, with simple explanations of what they mean. These would probably be aimed at younger children (8s and under), but our older boys have enjoyed them nonetheless.