I sometimes have crabsticks, smoked salmon & prawns with some salad. Alternatively you could do slices of various cold meats such as ham, chicken, beef with salad and pickles - pickled onions, gherkins or cornichons, beetroot. You could also have a HEB of bread or crispbread with these.
IIRC there is a recipe in one of the books you get when you join for a tuna nicoise salad - basically a tuna and boiled egg salad! Both DH and I love this particularly when we're away in our motorhome during the summer.
You don't say whether you are at home or work for lunch but if you're at home you could have main meal at lunchtime and have something like shepherds pie with mashed swede and carrot on the top.
Hope this gives you a few ideas.
Denise