• Sliced breads are the norm in most Western grocery stores and these are what is used to make most "standard" sandwiches, like peanut butter and jelly. You can get this bread made from many different ingredients (rye, potato, white, wheat, etc), and the different flavors will go better with some sandwiches than others.
• Loaf breads are basically sliced breads that haven't been cut yet, but get used in much the same way. This bread is usually fresher and cut thicker than normal sliced bread.
• Buns are small round or oval loaves that get cut in half to make the sandwich. This is common with hamburgers or Brioche sandwiches, but you can also use things like pretzel buns.
• Raised flat breads include breads like focaccia bread or panini. These have a similar texture to pizza dough or true flat breads but are thicker, which means they can be sliced to create a true sandwich.
• Flat breads include things like pita bread, naan, and tortillas. These do not make a true sandwich but instead make wraps or are cut in half and stuffed between the natural bread layers.