I work for a home health agency and everyone seems to bring in stuff ranging from post its, snacks, etc. I go with what my budget seems to fit that year and what I can find. There are about 30 people
I have done:
Dunkin Donuts Coffee Singles (brews a pot) 0.99 each - left a basketful for everyone to help themselves. You could also bring in a box of Joe and bagels and cream cheese/butters/jelly for everyone to enjoy then and take the coffee singles home for later.
We have a Pepperidge Farm outlet nearby and I found Milano cookies in a 2 pack for 4/$1 so I bought a bunch of those, bought a couple boxes of coffee singles (Maxwell House/Folgers sells - looks like a tea bag) and packaged them up pretty with cellophance bags from the Dollar Store. Nice little snack during the day.
For the immediate office girls I work with - last year I gave them each a pound bag of Dunkin Donuts coffee - they usually go on sale for 2/$10 around this time and you can get any flavor.
This year I got the Glade Flameless candles from Target when they were on sale cheap and were giving you a $5 gift card with purchase so they were almost free
and I found ceramic pottery mugs on clearance for $0.25 each and will fill those with chocolate for the nurses.
My DH does Lindt Chocolates for each of his co-workers and now they have the big bags 2/$20. Depending on how many you need you get a free plush animal holding chocolates free - reindeer if you spend $50, snowman if you spend $100 - so it's another gift off the list if you spend that much. ALSO they have a "lindt" club card and you get free chocolate by making purchases (I qualified for a free bar - think large Cadbury size - that will make a nice stocking stuffer for DH).