The document discusses two common types of external conflict protagonists face in fiction: person vs. the unknown/extraterrestrial, where the protagonist battles an unknown or incomprehensible entity like an alien race; and person vs. technology/machinery, where the protagonist fights dehumanizing technology that sees humanity as obsolete, such as astronauts opposing intelligent machines. It provides examples like The War of the Worlds and 2001: A Space Odyssey to illustrate these conflicts.