Mud bricks for building is the first thing that comes to mind. In fact the adobe already in the game is practically just that but without added mud.
Irl all you need is dirt, clay, sand, and plant fiber such as rice husks… All of which are already in the game.
Itd make a nice building alternitave especially if we could paint it with plaster.
Or itd be good to be able to turn it into normal soil for farming. Maybe have a way to turn soil back into the dirt/mud so that people wouldn’t just dig holes all over the town and then turn the dirt into soil so you cant fix it.
Also make it so that the big dirt can be moved like boulders so that we wont waste extra shovel uses. Or make it so that the shovel doesnt use uses when picking up or placing already dug dirt.