Fleshbox Volume 1 PBR Materials
20 PBR Materials in .sbsar format, also includes .jpg versions with all source maps (normal, roughness etc).
Fleshbox Volume 1 contains Skin, Bone, Guts, and other "meaty" materials for use in Unity, UE4, Substance and more. JPG version is also included which contains diffuse, ao, normal, roughness, and for some maps height, glossiness, specular and bump.
Drop directly into UE4 (must use the free Substance Plugin from Allegorithmic) and simply drag onto your object to apply - simple! Or, create your own variations from the jpg files.