Parsley and mint are also good companion herbs for tomatoes and deter a number of pests. Basil is also a favorable plant to grow near tomatoes and purportedly increases not only the vigor of the tomatoes, but their flavor as well.
Flowers such as marigolds keep nematodes from attacking tomato plants and their sharp odor confuses other insects. Nasturtiums help to deter whiteflies as well as aphids.
Read more at Gardening Know How: Tomato Companions: Learn About Plants That Grow With Tomatoes https://www.gardeningknowhow.com/edible/vegetables/tomato/tomato-plant-companions.htm