Photographic materials: Poly Haven, CC0-1.0.
Brown Mud 03 and Bark Brown 01: Rob Tuytel.
Rock Face 03: Dario Barresi (photography), Rico Cilliers (processing).
https://polyhaven.com/license
https://polyhaven.com/a/brown_mud_03
https://polyhaven.com/a/rock_face_03
https://polyhaven.com/a/bark_brown_01
Resized and packed into 256x256 texture arrays for this application.