I’m into the details of my Christmas Market trip, and I found this site to be very helpful. Of my list of 11 German cities where I’m staying, this had 8 of them in their main list with city websites. (The only three missing were Regensburg, Würzburg & Münster.) The info & especially the videos overlooking the markets have amped up my excitement to be there!
Happy planning!
https://archaeology-travel.com/thematic-guides/christmas-markets-in-germany/interactive-map/