My kids love anything we can stick on a party pick and call a kebab.

(I am overly-cautious and clipped the pointy part of the party picks off to leave a more blunt end.) We stick fruit chunks on party picks or combos of veggies. Whatever the kid likes.
They like mini-bagels with cream cheese or with peanut butter/a non-nut butter. They like pitas ripped up onto chunks to dip in hummus or actual little mini pitas to fill with ingredients when they get to school.
They like yogurt, babybel soft cheese wedges as well as the little round babybels in the wax. They like it if I send sliced fruit or berries in one container, yogurt in another, along with a bit of granola and they build a little mini-parfait out of it....minus any actual layers, of course!
They like dried fruit and love freeze dried fruit, but I send the freeze-dried fruit sparingly since it's pretty darn pricey in relation to the amount of food that actually comes in the package.
They like pasta salad, egg salad, and depending on the kid (and the phase in their life) chicken or tuna salad. (We are a primarily vegetarian family, but the kids are free to eat meat if they wish and occasionally they do.)
They DO see the Lunchables and ask for them and yes, we do let them have them every once in awhile.

We're fans of moderation around here. We figure if something is banned it becomes more attractive.
They have always been happy to eat any left-overs out of a thermos. Soup, pasta, mashed potatoes, casseroles, chili, even a burger or pizza slice cut into a few pieces. (Although they will both happily eat cold pizza, too.)We boil water in the morning when we first wake up, fill the thermos with boiling water and keep it that way while we eat breakfast and such. Then shortly before we have to pack the heated food we dump the water out. And that keeps the food hot until lunch.
They like to have a variety of crackers around to use for their grain. Triscuts & hummus or veggie crackers with cheese, instead of tortillas, bread, or pitas, for instance.
They also like breakfast foods like belgian waffles, mini pancakes, or oatmeal (The thermos again!

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We have little tiny squeeze bottles and dip containers that we send condiments/dressings/syrups to school in and they love that.
Right now my youngest loves anything he can spread or place on a tortilla and roll up. Peanut butter & banana slices; apple slices with cinnamon; cheese, tomato & cucumber slices, & ranch dressing; cream cheese and strawberry slice, you name it.
They like unique snacks. They love to go to the international areas of the grocery store (or get snacks in the mail from other countries) for small items to put in their lunches.
Neither of my kids are big on seeds & nuts, so they are absent from their lunches, for the most part. My oldest will pack some cashews once in awhile as an exception. This (the nuts) only works in schools where they are allowed, of course.
Sometimes they want a ton of variety and sometimes they eat the exact same thing for a year. Literally. My youngest took a cheese hoagie, an applesauce cup, a water bottle, and a drinkable yogurt every day for one year of preschool. It was basically an entirely white lunch. Talk about a lack of variety. But it made him happy and he'd eat it. So we gave him different foods at home and let him have his same lunch every darn day!
