I dont know that I truly know what a brat is, but my deer sausage is typically 60/40 with pork, and I tend to favor a salt, pepper, garlic taste. I cant find my recipe from last season to get the ratios, but I really liked it. And I've boiled them, grilled them, cooked in a skillet...all different but all good. I have to say though this last batch we used huge casings, and I discovered I much prefer a smaller casing.
Jalapeno/Cheddar brats are typically a well known combo. My buddy that used to work at a deer processor made a batch of blueberry/swiss brats that were awesome. It sounds like a weird combination but its amazing.
Tagging in....I'd love to see a Home Built recipe! I had a bunch made from a Moose years ago, and it was sweet to be able to grab a pack from the freezer for a quick meal....... With a big side bonus of knowing exactly what you were eating!