I just make double the amount of dinner every night, and me and DH both take the other half for our lunches the next day. If for some reason I haven't done this the night before, I tend to just snack on boiled eggs, nuts, salad veggies and dark chocolate, with some added fat (cream in coffee, mayo with veggies or something).
I sometimes do about 100g of bulgar wheat. With a load of cut up baby leaf spinach, some feta and beetroot (not pickled). Put a tablespoon of balsamic vinegar in. It's got some carbs in but it's not as bad as a sandwich and I find it filling.