Explorers League Achievement
Find all the items in the world
For this achievement, you need to have you keflings harvest all the groupings of rocks, crystals and trees around the map. Doing so reveals and collects various items such as gears, eyeballs and different kinds of hearts. Just keep looking and harvesting, and you should get this before the desert world assuming you cleared enough resources to find everything up to that point.
Thanks to "DM HavoX" for the tip!