Okay I am game. Items of some interest in an office:
Network cable. Remove the plugs and outer sheathing and that is 8 flexible copper wires for various uses including snares, lashing material and so
Fire Extenguisher. Handy makeshift battering ram for various entry senerios.
Rubber bands. Handy for various uses.
Water Cooler Jugs: Fresh clean water for the taking. Empty ones can be modified for various storage vessels.
Paper pencils pens: Paper for starting easy fires, insulation, nature uses.
Toilet paper: For the intended purpose, also insulation.
First Aid Kit: For first aid
Tape: Masking, cellophane tape is tape and can be useful in various ways. Like homemade bandaids using a papertowel or piece of cloth.
Breakroom: grab them plasic knives, forks and spoons. If fancy enough you might find a roll of aluminum foil grab that too for making a solar cooker.
Vending machine items.
Janitor closet: Soap, perhaps a nice toolbox.
IT Manager's office: Tools. some handy, most are too specialised to be useful.
Sissors: Cutting/skinning the hide of your food animals, makeshift knife once the pivot screw has been removed. Should be many pairs laying about in
Luck could be on your side and you find flashlights, batteries, hand crank radio, a pistol with a few rounds, and various other handy items that you
would see and decide as you scrounge around.