Never had any problems with window weights ,the old man even made valve seats out of them!
other stuff :- shock absorbers (as mentioned before) a good source of hard chrome bar and seamless tube,boot and bonnet struts ,the same but smaller,the usual stuff in cars ,drive shafts,axels rear and front wheel drive( the best cold chisel I made was out of a front wheel drive Mazda (Had to give it to the young bloke I had working for me as I was showing him a bit of black smithing stuff) Exercycles cast iron fly wheels, nuts an bolts. bits of steel tube (in non standard sizes)you might be lucky and get the meter of it and it works! Washing machines ,motors (large pancake motor (F &p) 3 ph motor Bosch (I think) both of these have permanent magnets (wind generaters?) Aluminuim stuff see Micheal Cox's article about casting build yourself a furness even if you don;t do any fancy castings you can pour metal into cans to make lumps for turning ,cat food cans are good, fly spray(here in Aus there about 300 long)
There is more but you might be getting sick of reading this!
Cheers Danny