My dds don't like sarnies everyday but luckily like lots of other things, which means I've been able to experiment - i suggest you do the same and find out what things go down well with your little ones. Some stuff we have regularly:
Proteins:
Leftover sausages, cut up in to chunks with something to dip like ketchup or relish
Quiche - they like ones with bacon and cheese, broccoli cheese, onion cheese, mushroom, roast veg, spinach, and ham.
Leftover dahl (lentil curry) with bread or chappatti to dunk
Pieces of ham, different cheeses, roast chicken, roast pork or beef... or a mix, with salady bits
Bean salad - chickpeas usually, mixed with mayo or pesto
Falafels (leftovers)
Tuna mayo a la tupperwear, but very very tightly wrapped over so it doesn't smell!
Don't often bother with eggs as they really smell no matter what I do
Carbs:
Pasta!! Deffo the staple - we have it with tomato and cheese, pesto, roast veg, ham, mayo, tuna, whatever!
Pitta breads
breadsticks
Rice cakes
oat cakes
melba toast
cream crackers
poppyseed crackers
Rice - leftovers mixed with some kind of dressing or just plain, they like it!
Sometimes fruit loaf with butter/jam as a treat
Fats:
Hummus to dip
nut/seed butters (obvi check for allergy policy)
I don't usually put whole nuts or seed in as they are little, so choking etc scares me.
Fruit/veg
Cut up raw veggies with a dip, such as cherry toms, celery, carrots, cucumber, pepper.
Fruit salad with whatever we've got
Little smoothie packets
Dried fruits
Fruit bars
If we've baked anything like flapjacks, scones etc, I might put one in. Hope that helps! x