Four common types of welding electrodes for Shielded Metal Arc Welding (SMAW or "stick welding") include 6010/6011 (deep penetration for dirty metal), 6013 (all-position, smooth finish for light work), 7018 (low-hydrogen, strong welds for heavy structural work), and specialized electrodes like Stainless Steel or Cast Iron for specific materials, all differing by their flux coating and application. These electrodes melt during welding, providing filler metal and creating a protective slag/gas shield, unlike TIG's non-consumable tungsten.