If you wish to stick to tradition, Quiche Lorraine consists of heavy cream, bacon, and European cheeses like Swiss, Gruyere, or Emmental (widely used in French and German cooking). Regular quiche, on the other hand, has many variations and you can pretty much toss in what you like, in terms of the different meats and cheeses. You can make it lighter by using half-and-half, or make it vegetarian by adding only veggies.