Here's what I've seen that works and are usually eaten: ripe olives, green olives, Kalmata olives, small sliced dill pickles, celery with some type of cheesy or sweet spread on them, grapes, fresh strawberries, carrot sticks with dip
Relish tray pieces that aren't eaten much: broccoli, mushrooms, cauliflower, zucchini, pearl onions, gherkins, large cherry tomatoes,
I've usually just added a relish tray to the dinner table or buffet...seldom made it for people to snack on before a meal.