The BIO category contains textures that are of organic nature but do not fall into any of the nature categories (na_xxx). This is a catchall for made-up biological textures.

Alien Skin Skyler Swanson	Old Bone Mark Naivar	Plague Skyler Swanson	Sphincter Skyler Swanson	Citrus Rind Jane Lin
Coral DarkSim - SkylerS	Fungus Skyler (Darkling Simulations)	Heart Muscle DarkSim - Mark Naivar	Muscle Fiber DarkSim - August Swanson	Raw Meat SkylerS -- DarkSim
Bumpy Coral Jane Lin	Smooth Coral Jane Lin