working in Telecom... I have come across tons of stock left over from installation projects... Lots of angle of various sizes up to about 3x3 or so, allthread by the ton, nuts bolts and misc hardware to build equipment racks and earthquake bracing required by code... Most if not all mild steel and grade 5...
Another good one is if you can get access to DRMO... I have a piece 3" dia and about 3' long out of an all terrain forklift...