This list of commentaries on Galatians published before 1800 remains very much a work in progress. For a sense of the ways in which it could be expanded upon were time available, see my course guide on the history of exegesis/interpretation.
This list is very far from complete. I have made no attempt to include all of the (mostly unpublished and untranslated medieval) commentaries listed on pp. xi-xiv of Mußner's Der Galaterbrief, HTKNT (1974), just for starters. It remains also unorganized by date. Needless to say, any of the commentaries listed below could appear in English translation at any time.