Condiments
Hot sauce, soy sauce, Worcestershire sauce, relishes, and mustard are condiments that can be stored for a long while in the right conditions and will transform any boring MRE into something utterly delectable.
Although it is not really a condiment, you should also consider keeping some dry bullion powder. It is great for adding flavor to prepackaged meals and can be added to things like casseroles, soups, stews, and more.
