Something light...back ijn the day they were called "finger sandwiches," but I'm sure that's a term that's no longer used. So, essentially, mini sandwiches on rolls or mini-croissants with chicken salad, cucumber spread, sandwich meats, etc. You can add a large salad if you want.
I was recently at a catered event which featured a "build your own cobb salad." There was a very large bowl with romaine lettuce mix. On a round tray, there wee beautiful strips of chicken, ham, cheddar cheese, montery jack, cucumbers, black olives, tomato, hard boiled egg, etc. On the side there were bowls of ranch and raspberry vinagrette. It was unique and quite attractive. There was a lot of ham left over...the chicken went first, so I'd make it with more chicken than ham.
Maybe some cut up fruit if you'd like and some chips or pretzels. The main thing is that if people haven't eaten lunch, you want enough food for them to not be hungry. However, it's also late enough that it's not really a luncheon, so you don't have to plan a full meal where someone might feel obligated to eat even if they've just had lunch.