Minor Adornments belong to the so-called "Collectibles". These are items that have no physical in-game object, but can be activated either from the Collectible menu, or the Quickslot menu. They can be unlocked by either getting in-game achievements, or through purchasing them via Crowns, Crown Gems or Seals of Endeavors.
Full list of all "Minor Adornments" that are available in ESO (Elder Scrolls Online). "Minor Adornments" are added to your collection and are unlocked for all characters on your account. Minor Adornments will override all your character's attire visuals, skin, Minor Adornments and physical features.