Written and illustrated as a kids book, but even adults will be edified by the stories here [1]: 101 Orthodox Saints. All are stories of faith and are quite inspiring. (Just a heads up, a lot of the saints were martyred, so you should consider how to approach those conversations with your kids. The book is delicate, but doesn’t shy away from the reality of their deaths)
https://store.ancientfaith.com/101-orthodox-saints/