So many maps. I have several full-size prints hanging in my office that were already mentioned. But if I had space for another, it would be this one by Mike Schley:
The Moonshae Isles was one of my favorite sandboxes within the Forgotten Realms, even though they weren't originally in Greenwood's FR. Despite being introduced in 1st edition, the area has gotten minimal attention over the years until 4th edition.
Shortly after the successful release of the
Neverwinter Campaign Setting, a handful of articles began to appear updating some specific areas of the Realms, like Waterdeep, Cormyr, and Daggerdale. These articles followed the idea of Neverwinter to update those areas into central hubs for thematic adventures based around the location, culture, current events, and history. Though not nearly the same scope and size of the hardcover book, it felt as though they were really on to something. Alas, they pulled the plug on most projects at the end so we may never know what could have been (and have not really seen since).
Of those articles that did appear with updated maps (Schley did similar ones for Vaasa and Cormyr), this one stood out as my favorite. The map itself is beautiful, and full of details. There are so many locations and names marked that invokes so many ideas. It is small enough to have a highly thematic and focused campaign.
But there is so much intrigue and conflict embedded in this region, it can never be dull. You have the eladrin returned to the elves from the Feywild, reclaiming their ancestral kingdom. You have the celtic-inspired Ffolk who venerate the Earthmother and contend with the outside world. You have the western kingdom which is the gateway to the outside world, bringing foreign ideas and people. The barbaric northlanders tend to raid those in the south. Wizards are regarded with fear and suspicion. The dark power is a dragon-like beast. Vampires have secretly become the rulers of one island. And then there's the underwater realms, the firbolg, the ruined wizard's tower, etc.
To me, this map represents so many possibilities and stories that have sadly been overlooked for too long.