My all time favorite is the "Homecoming: Harmony" series by Orson Scott Card.

It's based off a Mormon parable. Something in the deeper relationships between siblings and getting to deeper truths is usually what hits me the hardest. I need moral content, not just fantastical elements.

Only read the first 3 books though. The last two weren't as good, but I'll reread those first 3 every couple years.