Polish boy is the signature sandwich of Cleveland, Ohio, consisting of a kielbasa sausage, coleslaw, fries, and barbecue sauce in a bun. It is believed that Polish boy was most likely invented by a restaurant owner named Virgil Whitmore in the 1940s, who combined a smoked beef sausage with other available ingredients that he had in the restaurant.

Today, there are some variations on the original, such as the addition of pulled pork to the already huge sandwich that is Polish boy.

Corned beef sandwich is a popular food item that is traditionally consumed on St. Patrick's Day. It is both Irish and American, since it is believed that the sandwich was first popularized in New York by Irish immigrants during the early 20th century.

Typically, it consists of sliced corned beef between two slices of (usually rye or sourdough) bread, but there are numerous variations of the sandwich with added cabbage, mustard, cheese, or pickles.

Reuben is a melty sandwich consisting of a combination of corned beef, rye bread, sauerkraut, Russian dressing, and Swiss cheese. According to one out of many theories, it was invented in 1914 at Manhattan's Reuben Delicatessen by its owner, Arnold Reuben, when an out-of-work actress ordered something new, and Arnold made her a Reuben sandwich.

The combination of meat and cheese is not kosher, but the sandwich can be found in Jewish delis because it's a part of Jewish food culture and it's mostly eaten by people who are not strictly Orthodox. Just like most popular food, Reuben also has numerous variations such as Rachel sandwich, grouper Reuben, West Coast Reuben, Montreal Reuben and Reuben egg rolls. 

Roast beef sandwiches encompass a large variety of sandwiches filled with roasted and sliced beef as their main ingredient. They may be served hot or cold. The meat should be succulent, slightly pink, and thinly sliced, while the buns are typically soft and topped with sesame seeds or onion pieces.

As for the toppings, anything is possible, but in Boston, where roast beef sandwiches are one of the area's specialties, they are traditionally topped with cheese, barbecue sauce, and mayonnaise (called a three way when served together).