Well, OK, deli meats and peanut butter can be pretty processed, but mostly these are simple, whole foods. Women’s Health published this nice collection of simple meals, either just sliced together or cooked in one pan. The key to making this work is already having the ingredients on hand, so whatever looks good to you here (or whatever substitutions you’d prefer): put em on your grocery list!
Also note that the people offering these suggestions had grilled chicken and waffles on hand. These (and pancakes) can be made in batches and easily stored in the fridge for most of a week — a good example of how doing batch prep ahead of time can make your life easier, even if you’re not making formal meals that are partitioned out for sack lunches.