A location available at the end of early access it is to the south east just north of Amber Island

When you have upgraded the worktable to lvl 3, completed the quest, and the bridge has finished building, then you can explore the desert. When you first cross the bridge you will come to a small forest area with madcrabs around lvl 25. They will attack you if you come too close, but as the other creature's attack is not very harmful. 

In the forest area of the new part of the map you are able to find flowers that provide 20 herbs when gathered, and the Asteria flower can be gathered. 

Further in the desert area you can find Chili Pepper from gathering, and Cactus Fruit and Palm Jujube from the different kind of new trees. There are Palm Trees in different shapes, where the amount of hits will also differ from the trees. One kind of the new trees will not be cut by the Iron Axe, but require the Fisherman's Axe

While mining in the desert you can find sulfate, and Iron Ore, with the normal drops from rocks.

You will also come across Animal Skeletons in the desert.

Furthest in the desert there is a completely new area consisting of an oil site by the looks of it, shut down or abandoned years ago. New ruins will probably come in the future.