These textures are all recoloured versions of textures from Doom and Doom 2. They include different coloured lights, golden versions of the SHAWNx and related textures, water and lava falls, and so on.
A few of these textures were included in previous texture packs, but most of them have since been improved. They generally still have the same name, so you should be able to simply copy 'n' paste on top of the older versions.
For the sake of completeness, I've also included all the original Doom 1 textures. Some of these have been 'improved', as have a few Doom 2 textures (such as CRATx, DOORSTOP, and SUPPORT2).
Version 2 adds an additional 250 or so new textures (including several specifically intended for use in CTF maps), a couple of dozen new flats, and modifications to several textures from v1.
Much effort has been put into making certain v1 textures bear a greater resemblance to the stock Doom (2) textures; for example, the red marble textures are now a closer match for SP_HOT.
A word of warning: don't try adding new textures to this wad via WinTex. WinTex is incapable of handling more than a certain number of texture entries, and will corrupt the TEXTURE1 and PNAMES lump if you add even one more to this particular wad. You'll need to use another utility - such as SLumpEd, XWE, or DeePSea - instead.
ID Software for the original textures (from Doom 1, Doom 2, and the Doom Alpha).
Michael Mesko for the lava fall.
The author of neutered.wad for SUPPORT2, TTALL1_2 and a couple of others.
Modified Doom (2) textures
WinTex v5.0 Paintshop Pro v6.00, v7.00, v7.04, v11.00