Texture Pack Combiner by Cestral provides a batch file that generates a texture folder which individually selects textures from 3 different texture sources. Two of them, Skyrim Realistic Overhaul and Skyrim HD - 2K textures, are already used in STEP. The third, Serious HD Retexture Skyrim, is not used by STEP. It uses a lot more SRO textures (vs. Skyrim HD - 2K textures) than the STEP recommendations, and uses a few textures from Serious HD Retexture Skyrim.