I second all of these.
But I honestly miss South Pole, Atlantis, and Last Cave. While the latter two were pretty empty, they were still really cool atmospheric maps to explore. I fondly remember exploring some of the sunken coliseums with a friend, and even seeing an amoeba roleplayer by the beach. I didn't even know that Last Cave was a map before I stumbled into the portal. South Pole was quite the chill meeting spot. Not as many people as Stone Bridge or Bonfire, but I remember my forum friends hanging out on the hill when the other maps got too crowded.
Also not really game nostalgia, but the OG last post wins thread. Had some fun memories with that one.