I'd like to see:
* an Apparatus of Kwalish.
* Baba Yagas Dancing Hut - specifically the one that Paizo drew in their Reign of Winter AP.
Almost everything has already been done to death. The one area that is still lacking, imho, is female (monstrous) humanoids.
This Reaper Minis Kickstarter has the Dancing Hut and Baba Yaga, herself. I saw an Apparatus of Kwalish recently but I don't recall where.
More variety of the monstrous races is low. Especially with female representation.