If your tomato plants are growing in containers, I don't think I would plant anything else in with them. The reason for that is that tomato plants require a lot of water and they're heavy feeders. When the roots are confined in a container, they are already limited as far as accessing optimum amounts of nutrients and water. Adding other plants would only increase the competition, and risk weakening the tomatoes, which could invite diseases and insect infestations. JMO.
"Isn't it enough to see that a garden is beautiful without having to believe that there are fairies at the bottom of it too?" - Douglas Adams