We had two different tuna fish recipes - one with mayonnaise and one with ketchup.
We made sandwiches out of leftover chicken thinly sliced steak, or meatloaf.
Instead of just PB&J, we had PB&banana, or PB& honey. Instead of jelly we used marmalade or other types of jams - blackberry, strawberry, etc.
Instead of the above with peanut butter, we made them with cream cheese. One daughter liked the jams with cheddar cheese.
Sandwiches were made from meat babyfoods with pickles, lettuce & tomato.
Used omelets in sandwiches as well (egg sandwich).
-- fruits and veggies --
Everything and anything they like!
Apples, oranges, tangerines, kiwi, pineapple, peaches, apricots, grapes, applesauce, various melons, fruit salad, regular salad (which was always made different - sometimes even with the meal in it - like adding chicken, nuts, eggs, etc), raw carrots, broccoli, celery...
When combined with all the other lunch ideas, there was no end to the variety.
We made up a chart with all the different lunch ideas, and we all took turns preparing the lunches for everybody (I needed one as well) the night before and sticking the lunch boxes in the fridge (we had an extra one in the garage). Even by age 6, they are old enough to make lunches with a little bit of supervision. Later, when there were 6 lunches to make, when the younger ones had to do it, they teamed up with older ones so it went real fast.
My youngest is now 20. Since she has celiac and other food allergies, she still is packing her own lunch everyday. But now the variety and creativity that goes into her lunches astounds me!