Mmm, that's a difficult one. It depends which plan you're on too. I think peanut butter would be ok, better if you could get lower fat as fat doesn't combine well carbs. Low sugar jam (jelly) would be an idea. My father used to make sandwiches with salad items like watercress or cucumber. I would use scrambled egg but that would no tbe allowed on most plans.

I think a veggie burger wouid be fine.