Key Items are unique, non-consumable items that are essential for story progression, unlocking new areas, or triggering specific events. These include things like spheres, mission-specific objects, and items that grant access to new Dresspheres or Garment Grids. Collectibles, on the other hand, are optional items that often contribute to your completion percentage or unlock rewards. Examples include the various 'Al Bhed Primers' (for understanding Al Bhed), 'Cactuar Spheres' (for the Cactuar Nation side quest), and 'Crimson Spheres' (for the Den of Woe). Always be on the lookout for sparkling objects or interactable elements in the environment, as they often hide these valuable items. Consulting a specific guide for 100% completion is recommended for finding all collectibles.
