The options for an interesting and unique Bloody Mary bar are quite numerous. First with the standard ingredients, there are many choices. Don’t limit yourself to just options for the garnishes. Flavored vodkas like citrus, pepper, and bacon are readily available. Also instead of using regular tomato juice or Bloody Mary mix, you can have V-8 or Clamato juices for a change of pace. Offering different type of hot sauces instead of just Tabasco would be a way to go. Hot sauces can add more than just heat. Some are based more on vinegar than chili peppers. Horseradish can also be presented in more than one form, with the pre-bottled horseradish sauce or freshly grated horseradish.
Now getting to garnishes, salts and spices are easy options to dress up a drab Bloody Mary. Rimming the glass with different things is a great option. Have a bowl with an inch or so of lemon or lime juice, so people could dip the rim of their glass. Then on surrounding plates have an array of spices and the like to dip glasses in. Celery Salt, garlic powder, black pepper, Old Bay seasoning, seasoned salt, or even bacon salt are good choices.
Other ways to garnish, as you mentioned, are the standard celery stalk and green olives. But other than the obvious lemon and lime wedges, there are many alternatives you can present: Pickle spears, gherkins, jalapeno peppers, cocktail onions, cherry tomatoes, asparagus spears, pickled green beans and peppers, or baby carrots and corn. But your options aren’t limited to vegetables, there are plenty of proteins that make an excellent garnish, like strips or crumbles of bacon, boiled shrimp, sliced hard boiled egg, or beef jerky. Have some long skewers available as mixing and matching all the unique flavors and garnishes will be the talk of the day.