I would avoid dried plums as they are gonna be high in sugar/calories (any dried fruit is gonna have that "problem"). apples/oranges have good fiber. Grapes are too high in sugar. A little messy would be 1/2 avocado, save the other 1/2 for the next day (eat with a sprinkle of salt, 100
calories, good source of
fat).
If there is room in the freezer you could buy a bag of frozen, pre-cooked, grilled chicken breasts (to prepare: 1 min on each side in a 1000-watt microwave).
Toasted high fiber bread (40 cals/slice with 3g+ fiber) with spray-on
fat-free parkay/butter.
Natural (no sugar added) peanut butter to go on the toast.
At worst, you could leave the bread & PB at your desk if you have the room (but then it stares at you all day). Or you could bring 2 tbsp of PB in a small container along with bread in a sandwich bag.
Low
fat yogurt. I prefer Stony Field for the abundance of bacteria and they don't pasteurize too harshly.
(I'd love to bring Steam Fresh veggies to work, but they stink up the joint when cooked)
Hmmm, bag of baby carrots... Carrots are somewhat sugary but they have lots of fiber and vitamins to balance it out.