Different fats have different flavors. Chicken fat is widely used in Jewish recipes. I believe the term used is Schmalz. Calrified butter, known as Ghee in Middle eastern cuisine is another popular fat. Rendered beef fat is known as tallow and is a wonderful fat for frying potatoes. Duck fat is also a favorite for potatoes. Pork fat is known as lard, and is used in pastries. Of course, if it comes from bacon, it has that smokey flavor and is a favorite for frying eggs, and adding flavor to baked beans or anywhere bacon flavor is desired.
I have combined various fats, taking into account that each has its own, unique flavor. For instance, a combination of chicken and beef fat tastes very similar to turkey fat. Goose fat is similar in flavor to beef fat, etc.
The trick is to blend the flavors into something you desire, just like you blend the various flavors of herbs and spices. You can't just throw a bunch of different flavors together and expect to get something great. You can mix fats to achieve a specific flavor profile and get something great.
Seeeeeya; Chief Longwind of the North