Basil and tomatoes--perfect partners in the kitchen and in the garden.
Borage is often overlooked as a companion plant, but it is one that tops many lists.
Interestingly, beans and peas can help control humidity near tomatoes
Marigolds are excellent companion plants for many types of plants
Carrots can help to naturally aerate tomato soil.
Parsley is an easy herb to grow. It will help deter pests with its strong fragrance.
Garlic will help deter larger pests of the four-legged variety, too.
Nasturtiums make a great "trap crop" when used as part of an integrated pest management program.
Oregano is another tomato companion that is as great in the garden as it is in the kitchen