I add pork fat that I get from a local pork producer.Thats all I add for hamburger.For sausage meat I add any one of several commercial binder/spice mixes.I just recently made a great maple flavoured batch and am going to do a honey garlic batch on the weekend.
Dave

We put equal parts of deer and brisket, ground together they make great burgers..........and you don't have to advertise them as "Bambi Burgers"

We grill deer burgers quite often with a little garlic salt and regular seasonings, just turn them a little more often. My wife will use it for spagetti sauce and such before beef. If you want to add a little fat the pork is the way to go.