A Texture-Pack I made for CG_Trader. I use Agisofts Photoscan, Gimp, Krita and Blender. All work is done on Linux.
The source pictures are from the Himalayan mountains and some old towns in Europe.
The rendering is done in Blender via Cycles. The material setup-up is nothing special.
If you are interested in the Texture-pack: https://www.cgtrader.com/3d-models/scanned/various/scanned-various-texture-pack
Or if you want a really big Texture-pack, containing various textures: https://www.cgtrader.com/3d-models/scanned/various/mega-scan-texture-pack