Regarding my 200+ commentaries on Galatians, I have a few times been asked which ones are the best. This is a tough question. I suppose that if someone put a gun to my head and said that I could keep five of my commentaries on Galatians but had to throw the
rest of them away, then these (not in any order) are the five that I would keep. I would definitely include the newest Galatians commentary that I own, Galatians: A Commentary (Baker Academic, 2019), by Craig S. Keener, one of my favorite commentators and authors. Keener references my work on Galatians in a brief footnote on page 66, which also means that I made the bibliography and index. I would also keep the following by two of my favorite commentators: Grace in Galatia: A Commentary on St Paul’s Letter to the Galatians (Eerdmans, 1998), by Ben Witherington III; and Galatians in the Baker Exegetical Commentary on the New Testament series (Baker Academic, 2013), by Douglas J. Moo. The fourth one would have to be Galatians in the Word Biblical Commentary series (Word Books, 1990), by Richard N. Longenecker. This incomplete series 
is now published by Zondervan, which is working on completing the series. Last, but certainly not least, is The Epistle to the Galatians in the New International Commentary on the New Testament series (Eerdmans, 1988), by Ronald Y. K. Fung. This is the replacement volume for the original NICNT volume on Galatians in 1953 by Herman N. Ridderbos that was translated from the Dutch. Fung’s work has itself been replaced by that of David A. deSilva, The Letter to the Galatians (Eerdmans, 2018). This is a much larger and more up-to-date volume, but I have not had a chance to look through it yet. It may turn out that it belongs in my top five list.