Here are two variations of the mud material I made for the Swamp scene. Everything is made procedurally except for the leaves with needles. These I modeled in Maya, baked and imported their height and AO into Substance Designer.
I followed a tutorial by Daniel Thiger: https://www.artstation.com/artwork/5wJdA as well as a tutorial on how to make a leaf: https://www.youtube.com/watch?v=0RwdPIG8SQk&t=1860s