Plant globe basil or marigolds (preferably the old-fashioned smelly ones)  around your vegetable garden border to help discourage rabbits and encourage beneficial insects.
2. Tall sunflowers function as a trellis for climbing plants such as sweet peas, beans, and morning glory.
3. Plant hyssop and verbena around your garden to help attract pollinators such as bees and butterflies to help with pollination.
4. Spinach, parsley, basil, and arugula grow well in between tomato rows as the tomatoes will help shade them.