A ham sandwich is an all-time classic, but the addition of condiments can take it to the next level. Mustard, mayonnaise, and horseradish are all popular condiments for ham sandwiches. Dijon mustard is especially popular as it adds a bit of zest and flavor. Pickles and relish can also be added for a little extra crunch and sweetness. For a unique twist, you can also try adding jam or honey. Finally, a sprinkle of herbs such as oregano or thyme can add the perfect finishing touch.