The NIV Application Commentary, Karen Jobes. Helpful and a must for preachers.
Esther & Ruth, Reformed Expository Commentary, Iain Duguid. Useful preaching ideas.
The Gospel in Esther, Stephen Sykes. A bit fanciful in places but thought provoking.
Unspoken Lessons about the Unseen God, Derek Prime. Typical Welwyn. Not great deal of depth, useful for devotions.
God Behind the Scenes, Luter & Davis, Expositor's guide to Historical books. I didn't like this at the start but it sort of grew on me. Helpful for some study on Hebrew words and some interesting reflections.
Esther, Joyce Baldwin, Tyndale. Helpful.
Lectures on the book of Esther, Thomas M'Crie. Very helpful solid insights. Reprinted
Tim Keller (Redeemer Central)
Ian Hamilton (Cambridge Presbyterian)
Christopher Ash (Gospel Coalition)
Geoff Thomas (Gospel Coalition)
Andy McCracken (Sermon Audio)