I like to use the Special K protein meal bars. They're under 200 calories - wayy less than a meal for me - easily portable - go well with coffee. The honey almond ones are almost too delicious, but the chocolate and strawberry ones are pretty nasty, if that's what you're going for! :) You could keep a stash in your desk drawer for any day you forget to bring lunch or can't decide what to have.
A few veggies and dip and maybe a single string cheese.
Some canned fruit and a small spoonful of cottage cheese.
A pack of cheese peanut butter crackers and a Diet Coke.
One of those small microwavable soups or noodle dishes.
A single small slice of thin crust veggie pizza.
A small, unsatisfying portion of whatever leftovers you have in the fridge. I try to do this, because it helps me with one of my usual Lenten resolutions to reduce waste.
A small salad with a hard boiled egg as garnish.
An apple with a touch of peanut butter and a glass of milk. Or banana the same way.
Happy Lenten eating!