I like planting cartots early in the season to break up the harder soil levels and make it easier for the tomatoes taproots to get deepat those nutrients and makes then more drought resistant, i also plant lettuces and leafy shade loving plants at the base of ny tomatoes as a live mulch it keeps the soil cool and imhelps the lettuce griw even during warmer months. Chives and marigolds keep the pests away and. As well as sage, basil, garlic and onions as long as they arent actually in the sane ved ( dobt get along well in my nevk of the woods lol) oh and peppers love the. Warm temps of summer but if it gets too hot theu really suffer, not so if you keep then shaded by big tomatoes. A few more but those are off the top of my head hope these helped (p.s sorry about the typos im on my phone)