I have written 2 different Advent devotionals for my church. They are both very different but I wrote both to be helpful for people who want to get a better experience of Advent.
The Advent Hours Experiment is a devotional that I put together with my dad. It is a journey from December 1-25 that uses a simple liturgy of hours. If you are not familiar, this is an ancient style of praying primarily the Psalms throughout the day. Each day has morning, noontime, and evening hours that varies but can include Psalms, Bible passages, creeds, prayers, and Christmas carol lyrics. There are also nighttime prayers called Compline that are written for every week in Advent. If you have never prayed this way before then this is a great place to start.
The other devotion is title Christmas Reflection from Church History: Readings about Christmas and the Incarnation from the Creeds, Church Fathers, and Great Thinkers of Church History. For this volume I compiled great quotes and insights from all kinds of different figures in Christian history and laid them out. This is a great way to reflect on what Christmas and the incarnation means as well as experience some of the great figures of our faith.