You should opt for a brand that lists just a few essential ingredients. This typically includes a specific kind of tomato and salt for a bit of flavor enhancement.
Canned tomatoes also naturally include water, but some brands may use juice from the tomato instead. These natural ingredients are all you should look for on the label.
Added seasonings like garlic and basil are also problematic, but not for health reasons. They can alter the flavor of a dish and possibly ruin the finished product.