My favorite is Quiche Lorraine, which has bacon, onion and Gruyere cheese with a touch of nutmeg. However, I also like to make quiche with:
Boiled potatoes and onions (a Spanish tortilla)
Broccoli and cheddar cheese
Spinach and cheddar cheese or Swiss cheese
Asparagus, green onion and either Swiss or cheddar cheese
Breakfast sausage, hash browns and cheddar cheese
Mushrooms, any type od cheese and green onions
Italian sausage, mozzarella, Parmesan and/or Ricotta cheese
Ham and cheddar cheese
Ham, asparagus and Swiss cheese
Green chilies, cheddar cheese and/or Monterrey Jack cheese, with salsa on the side
Leeks, Romano cheese, and Swiss cheese
Bacon, shrimp, salmon or crab meat, and Swiss cheese, sometimes with potatoes or with sour cream or green onion or red bell pepper
Leftover ratatouille and Swiss cheese
Tomato Basil quiche, sometimes with oil-packed sun-dried tomatoes instead of fresh
Smoked salmon with Swiss cheese, maybe some Spinach or potatoes, and topped with sour cream and caviar
In other words, I like quiche. Sometimes I make it as a frittata instead, which simply means I don’t bother with a crust, but instead make it in my grandmother’s cast iron skillet.