I like to bring a black bean salad that works equally well as a salsa with chips, as a side or even a vegetarian main. Ingredients are flexible but here's an approximation I wrote up for friends who asked for the recipe:
1 pound dry black beans, cooked
3/4 - 1 cup lime vinaigrette (Newman's Own lime or light balsamic work well)
1 bag of Trader Joe's frozen roasted corn kernels (no need to thaw)
1 large red onion, chopped
4 green onions, chopped
2 bell peppers (red, yellow, orange or green), chopped
3-4 stalks celery, chopped
4 chopped fresh tomatoes or a can of Rotel
2 diced jalapeño or serrano chiles, or more to taste
small pile of cilantro leaves, chopped
While the beans are still warm from cooking, drain them well and toss them with the dressing.
Then throw in the rest of the ingredients and serve.
The frozen corn will thaw and chill down the beans so you can serve it right away. Or put it in the refrigerator if preparing ahead. Keeps well for several days.