Tree Roots on Muddy Ground
Tree roots stretching across muddy ground with rocks
 
Fern Texture Generator
It is a fern texture. With the sbsar generator file, an unlimited variations of ferns can be produced. Practically, a few variations are enough to mimic the real world.
Ground Covered by Maple Leaves
This woods is covered by fallen maple leaves making the ground red and orange. This texture quickly gives autumn atmosphere to any environment.
 
Long Grass Texture
It is a long grass which appears everywhere in nature. Putting it into your 3D environmental design can enrich the scene and make the rendered output look more photorealistic.

Suggestion: making use of clustering(aka. children) of particles can bring the outcome to another level.
Grass Texture Generator
It is a grass texture. It can be imported as a plane. 2 planes can also be put together to make a cross to mimic bunch grass. Then the planes can be scattered among the meadow. The 4th picture shows the result of such scattering method.

With the sbsar, tremendous varieties of grass can be generated with different colors and orientations.
Leaf Generator
It is a leaf generator. Leaves have loads of variations in nature. Every leaf is unique in the globe.

The most powerful tool is the leaf generator in the format of sbsar. Then you can adjust the parameters to generate desired leaves according to your 3d environment.

Usually, 4-6 types of leaves should be enough to create the randomness in the CG world.

Of course, this leaf generator is absolutely free.
Birch Tree Bark Texture
It is a tree bark texture. From its horizontal patterns and the peeling, we can tell it is a birch tree.
Tree Bark Texture
It is a tree bark texture. The bark's texture is prominent. It has cracks and bumpy surface. Moss can be found on the bark too.