There are lots of fun ideas in this space. I'll think about lanterns first.
A lantern that reveals a person's inner emotions.
A lantern that casts darkness instead of light.
A lantern that never goes out or won't set things on fire.
A lantern that illuminates the way home.
A lantern that makes footprints glow.
Floating lantern
A lantern that glows brighter in the presence of goblins or undead.
A lantern that can use any liquid for fuel. Any. Liquid.
A lantern powered by a captive fairy.
A lantern that glows when magic is being cast nearby.
A lantern that makes light which certain species can't see.
A lantern that can use a rare fuel to make light as bright as daylight.
A lantern that is haunted by an annoying yet loyal poltergeist.
Lantern Genie.
A lantern powered by singing.
A lantern that can accompany a performer by casting shadow puppets to visualize their song or story.
A lantern which casts shadows that can be physically harmed. Stab the shadow, hurt the victim.
A lantern which reveals a very specific illusion, like the hidden door to a secret hideout.
A lantern which let's you read any language that it is illuminating.
A ghost busters lantern that can slurp up evil spirits after they have been weakened.
A lantern thatbplays music instead of casting light when you use it.
A lantern which causes synesthesia for those that see its light.