Let me then introduce the three wall sets.
Borealis Hull Walls
[img width=750 height=357]http://i39.tinypic.com/218ktu.png[/img]
"The Borealis, originally known as the Hyperborea, is a location and chapter cut from Half-Life 2. It was to be set between two other cut locations, the Air Exchange and Kraken Base, and to be the last location of the third day, visited during the night. "
See this article for more information!
While the Borealis has re-emerged as a canon location in the future Episode 3, these textures belong to the original design. They are all named 'hull', and are metal textures.
Unused Textures
Just a small set of some textures that once belonged to the 'e3_industrial' and other related maps (the 'Combine Factories') cut from the finished game. These are merely included for curiosity reasons, and have some mixed materials. This also has some very early Citadel textures that were modified or refined before being introduced in the finished game. Read more about the Factories here.
Valve Building Template Walls
[img width=750 height=435]http://i40.tinypic.com/uu2at.png[/img]
These are some early 'Building Template' textures, which are mostly recolored sidings of different type. This set includes a bit of brick, and a bit of painted siding. There's no special story attached to these, but it's a shame to let them go to waste. (Some may have been reused in future locations, but they are all grouped in a Building Template category.)
Enjoy! More to come in the near future.