The best ketchup is the spicy Whataburger ketchup. But I don't eat ketchup anymore. I like hellmanns real mayo and classic yellow mustard mixed up.
Not that's another thread. I always buy either Hellmann's or Blue Plate. Heinz makes a very good mayonnaise but the only place I've ever seen it is in the little packets in some convenience stores. I usually buy French's yellow mustard. For a burger I want yellow mustard but for some sandwiches or poboys I like different kinds of brown mustard.
I love me some spicy brown mustard, that shit mixes well with mayo too for a little added kick. I usually use it to dip or spread on chicken breast.
Not a mustard but Zatarain's remoulade sauce works well with a chicken or turkey sandwich. Haven't tried it as an actual shrimp remoulade sauce though. I make my own in a blender from an old River Road cookbook.