I need an idea for a tasty yet simple starter for a dinner party for my friends.?

I won't be preparing it my own kitchen so something that is easy to make or could be mostly prepared in advance would be best. We've been meeting up to prepare joint meals for years and we've been through dozens of classic recipes and I'm running a bit short on ideas. Oh and one of them is gluten intolerant, so no recipes containing flour. Thanks in advance!