I like to put pistachios. They seem so popular these days. You could even do any kind of candy. Kisses, mints, peppermints, gum or anything you like. You could even customize them a bit.
How about even a couple for the whole group? You could fill one with chap sticks of different flavors/brands. One you could fill with small hand creams from Avon or other sources. I don't know what kind of office you have or what you do but a jar of pens might be nice. You might put a jar of coupons or small cost gift cards for local restaurants like pizza, Starbucks or fast foods. Toss in menus too.
I worked for a nurse call center and one year made bags that were about 12 inches square with a draw string closure. I lined them fully. One each draw string I used letter beads to spell out their names. Everyone loved them and as new people came on board, the manager asked me to make them for them also. I had a lot of scrap fabrics at the time but not anymore!