I've found all sorts of things dumpster diving for example:
Furniture: armchairs, sofas, dining chairs, end tables, coffee tables, bookshelves, dressers, all low to mid quality.
Electricals: cheapest tv, microwave, stereo, cheap computer, expensive tumble dryer, washing machine and even a fortune cookie machine.
Quite a lot of small decorative items, many insects and rocks including some tiberium and those from WA locations, insects don't count for collections at all but rocks and metals will if you take them out of family iventory put them on the ground and collect them again. Oh and the tiberium grew unlike the consignment store one, I guess because you can collect it normally if placed on the floor.
In all when starting out or if you need some cash it's not a bad way to spend an afternoon, you just get a bit nauseous and smelly.