My struggle has been that my husband doesn't have access to a fridge or a microwave at work, so finding food is harder as the range aside from sandwiches is a little limited. I send him with his food in an esky.
I did a fancy salad at one point, with cold pasta, dressing, baby spinach, feta cheese, olives, and whatever else salad-like i had on hand, he seemed to enjoy that.
I also did cold dogs for awhile, the hot dog roll, with a hot dog sausage (those type of sausages don't actually have to be cooked) and the tomato sauce (ketchup) and mustard and stuff in a little container and he can put it together at work.
Those roles at the shops with ham and cheese on top are good snacks. Another thing is sending the ingredients and having him put together a flat bread wrap with lettuce tomato cheese and some tuna or cold chicken or something.
As for meals you can heat, I used to attend college and had a microwave there. I found leftovers to be the best. We almost always had leftovers from the night before, or I would cook a batch of, say, chilli and rice and freeze it in separate serves.
Hope that helps, and if anyone has pack lunch ideas for someone without a microwave let me know!