tree bark
Canned tuna, saltine crackers, any kinda fruit, bits of cooked chicken, rice cooked any way really, carrots, popcorn, pretzels, celery, nuts, cherry tomatoes. You could probably take those things of salami and just eat the slices lmao. If you have one of those thermal package-able flask things you could put tomato soup, even chicken noodle soup. Speaking of noodles if you have access to hot water you could take those noodle cup things probably. Sandwiches are your best bet but I totally understand getting burnt out on sandwiches lol.
Order a bunch of MRE's and whip them out at work and make everyone think you're crazy. Doubles as a back-up for the nuclear apocalypse.