This WAD file contains textures from older versions of Half-Life that are not in, or different from, whatever is in the default 'halflife' WAD. Contents include some Valve employee's pierced nipple from the Half-Life: Day One demo, an awkward amount of pinup posters, additional textures to texture sets, quite a few GENERIC textures, and Albert Einstein.
Will update this to add any new textures if new sources are available or if there's something I need to fix.
Hope this proves to be useful for someone!
Updated to fix more errors, and to add a few more textures.