Flowers are both a beneficial and attractive addition to a bed of vegetables. They have a variety of uses, depending on species. I always grow sunflowers in the veggies because they are attractive, thrive in the same conditions as vegetables, attract hordes of bees, and have tasty seeds at the end of the season. Some people grow flowers in among the vegetables solely for pollination, but others use the flowers artfully to create an eye pleasing picture. Good flowers for vegetable gardens are bright, long lasting annual plants that have a long blooming season. They should be upright, or climbing if you have a support, and preferably attract plenty of insects. Zinnias and Cosmos are some good ones. Also, some flowers, such as nasturtiums and marigolds, are good for companion planting with various vegetable crops as pest deterrent.