The list is as old as writing itself. The Ten Commandments is a list. The Code of Hammurabi (the first code of law, written about 4,000 years ago) is a breathtakingly plain list of hundreds of offenses and the punishments for committing them. Each time you jot “milk, eggs, Advil” on a scrap of paper before leaving the house, you are behaving like an ancient sage. The list is a primeval device, born from two hardheaded desires: to avoid unnecessary repetition and to reinforce the sense that items belong together. It has survived because of these twin efficiencies.
They can maintain the appearance of a sentence; they can maintain the appearance of a paragraph; and they can be formatted vertically, with bullets, numbers, or letters. The first two shapes do not jump out when the reader glances at the page. The vertical list does. Whether the vertical format is appropriate in a short (two- or three-item) list therefore depends on whether you wish to heavily emphasize the items. It is usually the best choice when your list is lengthy.
Only a comma is required for clarity when you list single words or short phrases. In the following examples, note that the serial (final) comma is included.