Minecraft wiki entry for Decoration, associated text: Armor Stand - Immobile, player-like entity that holds armor
Banners - Hangable wall block that displays customizable patterns
Bookshelf - Block that enhances enchanting tables
Campfire - Block that produces a column of smoke and provides light and cooking when lit
Candle - Floor block that provides a variable light level when lit; can be dyed
Flower Pot - Floor block that can hold a plant
Heads - Hangable wall & floor block that resembles certain mobs and even players; can be worn in the head slot
Item Frame - Hangable wall & floor entity that holds an item
Lantern - Hangable ceiling & floor block that provides light
Lectern - Block that can hold a book
Painting - Hangable wall entity that can display certain artpieces
Sea Pickle - Floor block that provides a variable light level when submerged in water
Torch - Hangable wall & floor block that produces light