You've probably seen similar textures to several of these before, but I've remade a lot of them (the TEKGREN textures in particular - which I actually plan to improve further, as there's a lot of obvious copy'n'paste at the moment).
BLACK, CEIL4_1, CEIL5_1, COMPSPAN, and FLOOR1_6:
Spoiler:FLAT1, FLAT19, GRAY, ICKWALL, LABWALL:
Spoiler:MARBLE, METAL, METAL2, and SHAWN:
Spoiler:STARx and TEKGREN:
Spoiler:WOOD and TANROCK3:
Spoiler:See this thread for various gothic-themed sets (including several SUPPORT3 variants), and this thread for numerous brick sets.