Targets for dumpster diving

When searching for what others don't  want, what sort of items are you especially looking for.  Of course, targets of opportunity are always fair game, but what are those items you keep a special eye out for?  For example, for me it is pallets.  I always have a use for them.

I target food/compostable items - especially items that can be used for human consumption, as well as lifestock feed items.  I hate to see compostable material go to the landfill.  These are my primary targets, but anything else useful/donatable/saleable are also snagged, time and space permitting.  
Lumber and scrap metal for projects are also good items.  

I used to target food but I found either vegetables that my family won't eat or empty carbs that they will.
I still stop in at Aldis for the easy picken's.
Just picked up two bags of onions, which I might replant, whole, or eat, cooked.
If I had more chickens, I would go more often.
As it is I can easily bring home a huge box of bananas that they struggle to deal with.
I share a lot of  what I find with the homeless, but only stuff I would eat myself.

Construction dumpsters are golden, and a subset of construct dumpsters are hospital remodeling dumpsters.
Where I live hospitals are in a constant state of remodeling, so they always have a dumpster dedicated to  the waste.
Most of theses hospitals are located within a few miles of one another, so hitting a few at a time is doable.

Places that deal in lawn care machines and places that deal in handicap accessories both tend to have heavy duty hardwood skids avaliable for the asking.

Cardboard boxes are a good filler for when other things are not available.