Homemade are the best.
1lb Ground elk, deer or moose (all very lean, and yes I hunt), some fresh breadcrumbs, 1 egg, spice it up depending on my mood, anything from plain s&p to greek seasoning. form into 1/4 lb patties and grill to perfection.
Topping selections are endless from the classic, lettuce, tomato and cheese or you can vary the topping to match the spices you put in the meat. Greek spices - tomato, onion, peppers, feta. Mexican Spices - avacado, tomato, onion, monteray jack... the list goes on