You don't say how old your kids are, but I recently had a very similar conversation with my 7yo DS1. He goes to day camp, and the camp day is actually longer than the school day, so he's asked that I pack him more snacks (in addition to his lunch), and more varied snacks than what he's been getting. He is a kid who has always loved appetizers - I think he loves the idea of picking from lots of little things rather than eating lots of one major thing. So - more work for me, but a way to keep him interested in healthy eating, right?
Turns out his major interest was in getting me to purchase snacky stuff like chewy chocolate chip granola bars, fruit by the foot, etc. I did buy freeze-dried apple chips (expensive, but they were on closeout so I got a bunch for half-price), but in the end, what worked was playing around together to figure out some things we could prep in advance and he could eat on the run. Here's what we came up with:
*Trail mix (he likes walnuts, pumpkin seeds, dried cranberries and chopped, dried apricots - I put out an assortment of possible ingredients and we had fun making various combinations)
*Muffins - I make a double-batch on Sunday morning, using a basic recipe and customizing it at least 4 different ways ( so we get 6 each of 4 kinds). DS1 likes to mess around with combinations and has hit on some great ones - pumpkin/apple/walnut was a favorite, as was blueberry/lemon/coconut. I freeze these in ziploc bags and then pop a frozen one in his bag every day - they thaw by late morning. (I get that these can be like cake, but I make mine with ww flour, ground flaxseed and minimal sugar so I feel pretty good about them.)
*Baby carrots and pita triangles with bean dip (I just whiz black beans and our favorite salsa in the food processor, but you could probably get a lot more creative )
* Guacamole and pita triangles or corn chips - I use the Moosewood low-fat recipe which is made with cottage cheese - if you eat dairy this recipe is brilliant as it sneaks in a little extra protein PLUS the lactic acid keeps it from going brownish in the container - stays a lovely pale green!
* Tapenade and French bread slices - not every kid is an olive-lover, but mine is, so he thinks this is a cool treat. He likes to mix up the olives we put in it
*Antipasto - we use olives, cherry tomatoes, random pickled veggies from the gardiniera mix at the Italian store, cheese triangles, leftover cold roasted veggies (cauliflower is great as it holds up well), etc.
And of course popcorn - so far I've just sent plain homemade popcorn in ziploc baggies, but there are lots of ways you can jazz up popcorn by using different spices, etc. We have a friend who makes his with olive oil then grinds on black pepper and a bit of fresh-grated parmesan, which is amazing!