The Dreamlands Surface Monster expansion consists of 2 Shantaks, 3 Gnorri, and 4 Moonbeasts.
Both Dreamlands Monster expansions are for use with ANY map. Yes, they can be used with the Dreamlands map as well, but they are not exclusive to it.
Each monster has a special ability inherent to it, which is described on its loyalty card. Shantaks have the highly useful ability of carrying a Cultist with them when they move, so you can move two units for just 1 Power (as long as one is a Cultist, and the other a Shantak). Gnorri, Lovecraft's little-described amphibious horrors, give you a new boost towards victory. The Moonbeasts have a particularly obnoxious special power which makes them the bane of the other players.