Mostly tiling textures, in your example the things that don't tile, are the barrels, though the barrel is reused. The beige cylinder on the left side, and the foliage. The tre trunks do tile though. Most of the variation work is done with lighting and decals.
I'd say, to take the concrete walls as an example, unwrap it so that they can share a single tiling texture( or perhaps 2 variations of it if you want a little bit more..variation) and then use decals or other techniques such as blending dirt textures based on vertex colors, to add some dirt and grime to it.