-the emergency terminal in shelters could begin with a mission when you start(some are broken and you need to repair them)
-survivor notes could have coordinates for stashes and LMOE shelters
-terminals could (depending on your computer skill and some USB software) be connected to survivor/science/military networks and occasionally generate missions
-radios that get amplified by a long-range antenna from radio stations(that you need to repair/build) can also give missions
-dead military squads and scientists could sometimes have orders that lead you somewhere(infested areas/portal expeditions)
-heist plans: found in a basement where someone planned how to break into a bank/doctors office/police station/jewelry
-antique stores and cathedrals could have ancient tablets that lead you into a deep mine or a portal in search of an artifact
-visions/dreams - when infected by fungus, blob, or wielding an artifact, during feverish dreams, something commands you to destroy another artifact, clear a triffid grove or remove/deactivate some gadget left by scientists that hurts the “faction”