The foods can change occasionally at Biergarten, but from memory they have the following:
At the salad bar, there are greens, macaroni and bean salads, potato salads, tomato, cucumber, and beet salads, plus some cheeses and cold cuts meats.
For diches - there is usually beer cheese soup, a selection of sausages (probably mostly pork) and brats, roast potato, roast chicken, a seasonal fish (I seem to see salmon the most), meatballs (beef), and schnitzel (pork). Saurkrauts, red cabbages, spatzle (pasta), and a roasted pork are usually available too - and various vegetable sides like beans and potatoes, rolls and pretzel breads.
There's a aelection of 8-10 small serving desserts - cookies and brownies, along with fruit cand cheese cakes, and apple strudel.
It's obviously pork heavy being German - but the meatballs, roast chicken, and fish dishes would be the main alternatives, as well as vegetables, salads, and there's always the kids meal options you can throw in - such as mac and cheese, chicken fingers, etc.