I’ve been using the National Archives of Scotland (previously Scottish Record Office) online catalogues for many years. Now it’s part of the National Records of Scotland, and I’ve just been trying some more catalogue searches, and found something new for me. The NRS has lots of plans for places in Scotland in the past, including maps, sketch plans of places, and architectural plans. And these seem to be largely tagged by place.
Searching for the place tag for Melrose parish finds 228 of these RHP maps and plans, from the 18th to the 20th centuries. Check out the list to see if any might concern your ancestors, depending on when and where they lived. Contact the NRS for further information on accessing these records, including arranging photocopies or digital copies.