Toasted, melted, grilled, or plain?
		
		
	 
Yes.  Yes.  Yes.  Yes.
	
	
Brie, Blue, Monterey jack, cheddar, American, Swiss, Cotswold, havarti, provelone, feta , Mozzerella, muenster, etc.
(I have accepted cheeses as my personal savor.)
	
	
White, wheat, sourdough, rosemary & olive oil, rye, pumpernickel, pretzel, beer bread, bagels, pita, roasted garlic, onion rolls, French, biscuits, naan, etc.
	
	
Depends on the sandwich.  I often add herbs like dill, black pepper, garlic powder, onion powder, parsley.  Occasionally, something like olive oil, BBQ sauce, mustard or steak sauce will pop up.  
Veggies like sun-dried tomatoes, sautéed mushrooms, or onions (raw or grilled) are solid options.
Tabouli works well for some combos.
There's a place near me whose BLT is toasted with 
brie[/I, lettuce and tomato.  No bacon.