Any cheese that melts easily could be used for raclette but it is best if they have a mild flavor, creamy texture, and nutty flavour. Some good options are Brie, Gruyere, Gouda, Swiss, Fontina, Cheddar, Jarlsberg, Appenzeller, or Emmental. In general you want to go with a younger cheese for a milder flavor. Aged cheeses will generally have a stronger flavor.