I use @Michael_Prescott’s Trilemma maps more than any other. Been getting lots of use out of the free adventures (with a hardcover collection now being Kickstarted). I love the adventures themselves, but just as often I use the evocative maps with fascinating situations as scenes for my own material. Michael posts the unmarked map images on the blog so you can safely reveal them to players.
It was the maps that got me into the Harn setting from Kekestia Productions and Columbia Games, and I think they are still lovely all these years on. What they introduced me to was the idea of ‘detailed’ maps at the scale of Kingdom down to settlement for use by the GM and ‘Poetic Maps’ to share with players. I still use them to help visualise locations …
I love how Dyson Logos’s style has evolved. I mean, look at this recent example of the Isle of Kheyus:
Other map illustrators I love include Elven Tower (Derek Ruiz), Blue Sword (Caeora, mentioned above), and Jared Blando, whose work has appeared in a few official and 3rd-party D&D 5e supplements.
Related: I love small artistic flourishes on the maps, like fossils in the dungeon walls or decorations on the edges of the map, even if they’re never visible to players because it helps me as a GM feel more “in the world” and thus I can communicate that better to the players.
Read the initial post and immediately had this exact thought.