When I am spending a chunk of time in food prep., I often just grab a half liter bottle of Barefoot Pinot Noir, or Cabernet Sauvignon and make a reduction to be saved and used as a sauce base for other dishes. Bourbon and sherry, per Pete's approach, adds another excellent background flavor layer, as does red currant jam (home made is fabulous stuff), cranberry sauce w/ whole cranberries, or thimble berry jam (A group of Monks in the Keweenaw make and market it up here.). If you can find fresh raspberries and blackberries, add these to the red wine reduction and a splash of bourbon or sherry a minute or so prior serving. Do not stir the raspberries...
Major Grey's or Crosse and Blackwell's, Hot Mango Chutney is also a good sauce base choice to thin with bourbon or sherry for seared duck dishes. Chutney is not much different than our jam... This makes a great table sauce for ruffed grouse as well.
Dijon mustard, canned whole cranberries, and sherry, with course ground black pepper (proportions determined by your tastes for sweet vs. bitter) added in the last few minutes of heating makes a very good sauce for venison, waterfowl, and bear.
Red curry sauces paired with grilled or seared duck pair well with strong flavored meats like waterfowl. S & B market a really good Japanese curry paste in bar form with the logo: Golden Curry on the box header. They offer three heat levels, based on consumer preferences.
You can also make a Satay Peanut sauce off a base of Sambal Olek Thai red chili paste. Birds eye chilies are pretty potent, so don't get carried away... Just grab some chunky peanut butter, a lime, low sodium soy sauce, ground ginger,brown sugar, and some coconut milk. This is a good mix with teal, wood ducks, or pintail. I also have used this with grilled sharptail with excellent results. Add a little applewood to the charcoal...
I use a mortar and pestle (Target sells a nice porcelain unit.) to grind dried Juniper berries, with coarse ground black pepper, ground bay leaf, and sea salt combined, all applied as a rub prior pan searing duck breasts or venison chops. This makes a great German dish. After searing the breasts, let them rest on a separate plate. Add a splash of sherry to reduce with the pan crumbles and drippings, prior adding a half-pint of heavy cream. Bring back to a simmer and fold-in cooked shitake or honey mushrooms. When the sauce returns to a slow simmer, reintroduce the duck breasts;heat for about five minutes on medium; serve with a brown and wild rice mix.
Another option is to peel several garlic cloves (4-5), add 1/4 stick of unsalted butter, and half to three quarters of a cup of extra virgin olive oil to a backing dish and roast at 350F for a minimum of a half hour. I add cayenne and some course ground pepper medley. When cooled, pour this into a food processor to emulsify the mix and store for use as a baste for grilling duck, goose, or venison. Making this with some added roast jalopeno peppers yields a really good variant or venison.