Onion Sauce: Add 1/4 Cup minced Onion to the Butter and sauté until tender.
Paprika Sauce:  Add 1/2 to 1 t. Paprika to White Sauce at the end.
Yellow Sauce:  Add 1 Yolk over very low heat or double boiler and a dash of Cayenne Pepper to white Sauce at the end. 
Wine Sauce:  Add 2 T. White Wine at the end.
Lemon Dill Sauce:  Add 2 T. Lemon Juice and 1/2 t. Dill at the end.  Stir to incorporate flavors.

Basic Chicken Gravy (master recipe)
To the Onion Sauce recipe'. Use Chicken broth for the liquid, (or 1 large Chicken Bullion cube dissolved in boiling water)

Creamed Veggies (master recipe)
To the Master White Sauce, add 2 cups cooked veggies at the end and heat until incorporated.

Cheese Sauce for Veggies or Macaroni
To the Master White Sauce recipe, Add 1 Cup Grated American Cheese and a dash of Paprika at the end and heat over low heat while stirring until melted.

Basic Country Gravy (master recipe)
Make a thick white sauce by increasing the Flour by 1 T. Use a combination of Milk and a meat bullion cube, or meat drippings, and extra pepper.
Great over Country Fried Chicken Steaks,
and other fried boneless breaded meats and poultry recipe's

Master Brown Sauce
2 T. Butter
2 T. Browned Flour (brown by baking it on a sheet at 300* in the oven for 10 to 15 minutes).
1 Cup Beef Stock (or bullion dissolved in 1 cup water)
Salt & Pepper.

Follow cooking directions for White Sauce.
Variations:
Wine Sauce: Add 2 T. Red Wine at the end.

Giblet Gravy: Add chopped cooked Turkey or Chicken Giblets at the end and cook until heated.
Onion Sauce:  Add 1/4 Cup minced Onion to the Butter and sauté until tender.
Also can use Variations to the White Sauce.
Basic Brown Gravy
To the Onion Sauce recipe'. Use Beef Broth for the liquid, or 1 large Beef Bullion cube
dissolved in boiling water. Add Mushrooms to the onion for extra flavor.