Texture, followed by a lowercase texture file name, for instance Ttexa loads the file avatar:texa.cmp. If the T is followed by a number, it represents a frame of an mov file, and the number is the frame number, 1 for the first frame. Otherwise the texture is a cmp file. Next comes the texture file name, which must consist entirely of lowercase letters. The texture name may be left out, in which case the last texture name given previously in the avatar string is used, or the basetype if there is no previous texture name. So in the avatar amy.0PT1HTZT5sam.rwg, the pelvis uses the first frame of the file amy.mov, the head uses the file amy.cmp, and the tail uses the fifth frame from the file sam.mov.
A compiled list of texture sets known, to me, is on pastebin for reference.
Textures are called from a series of 3-9 textures in a combined "set".
T2buh
Format: T#setname
T - Texture
2 - #2 of 9
buh - set buh
T4charlie - Worlds Logo
T5charlie - Sapphire
T4demon - Turquoise
T4elfin - Emerald
T4pegasus - Marbled 1
T5pegasus - Marbled 2
T6pegasus - Marbled 3
T4somgirl - Stars on Black
T5somgirl - Black & Purple
T4ogre - Orange Rectangles
T4orangutan - Orange swirls
T4rap - Green leafy pattern
T4sty - Elephant-skin
T4creature - Snake-skin
T4golem - Alligator-skin
T4kangaroo - Brown Leather
T4monster - Red & Black
T4glubber - Lime rectangles
T4avita - Red & Blue
T5minotaur - Armour plating
T6minotaur - Gold & Brown
T4bigfoot - Animal Fur
T4achoo - Camouflage
Thornybody - Green with Blotches
Tyankstripe - White with Blue Stripes
Tyankshirt - NY symbol
T4flutter - Invisibility of selected area
T1annie - Smoke
T1eni - "Kiss Me" on Violet
T2eni - Star-shaped flower on Violet
T3eni - Star-shaped flower on Blue
T4eni - "Kiss Me" on Yellow
T5eni - Star-shaped flower on Yellow
T6eni - Green zig-zags on Yellow
T7eni - Cyan & Magenta Vertical Stripes
T8eni - Purple Spots on Green