From Blender for Architecture
Materials are classified by category. You can find materials for other rendering engines linked to blender too ([Yaf] for Yafray, [Pov] dor POVray...)
Metal (chrome, bronze, copper, iron, steel, rust, platiné..)
Mineral (marble, granit..)
Glass, transparent plastic...
Wood (parquet, flooring, furniture, painted..)
Wall (tapisserie, papier peint...)
Ground (carpet, tile, soil, lino...)
Nature (tree, grass, leaves...)
There not many materials for architecture available on the net.