Image: Naughty Dog / PlayStationOfficial screenshot from Naughty Dog / PlayStation.
Look for the Light is the gold trophy for picking up all 31 Firefly pendants in The Last of Us Part I. Pendants are spread from The Quarantine Zone to The Firefly Lab, and several hang out of reach until you shoot them or knock them down.
Davidson's pendant in The Outskirts lies underwater in the stone rotunda. Warren's in The University only drops from the bloater in the dorm, so you must kill it. Riley's in Lakeside Resort is already in Ellie's backpack, but it only counts after you open the pack and look at it. Stewart-Seume's in The Firefly Lab sits behind a shiv door on the sixth floor.
Dying or quitting can roll back a pendant you grabbed after the last autosave, so check your collectibles menu before moving on.