Here is one I have used a few times and had trouble keeping it long enough to enjoy more than a day or so, course with a teenage boy in the house not much of any food lasts much longer than dinner time.
1/3 cup salt
1/2 cup Brown sugar
1/4 cup molasses
4 cloves garlic-smashed ( or sub 1 1/2 Tbs minced)
1 lemon - sliced, squeeze and add all (or sub some bottled lemon juice)
2 Bay leaves
1 tsp thyme
1 1/2 Tbs black pepper
1/4 cup Worchestershire Sauce
1 large onion - chopped ( I have subbed onion powder, but better with whole)
Mix all together in large zip lock bag, add venison roast, add water to cover. Seal well, shake well to mix. Brine for minimum 12 hrs, shaking bag periodically. You may even want to inject using the brine during the brining period.
Good luck, barkerb. I hope this helps, and I hope your venison turns out great.
Mark