Red Banner

Six of them come off a loom in plain colors, and those are the only ones you can make. Everything else in the group is found already hanging somewhere and has to be knocked down and carried home. Floating islands, pyramids, the underworld ruins and the dungeon each have their own designs, and one more exists only as a drop from the Dark Mage during the Old One's Army.

Only half of the underworld designs generate in any given world, so a complete display needs a second world, a friend, or a lot of patience. Nothing tells you which ones you got until you go and look, which makes it worth checking early if you care about the full set.

The faction flags are not decoration where you find them. After Plantera, the flag hanging in a stretch of corridor matches the wall behind it, and the pair of them tell you which group of enemies spawns there. Reading them on the way in is how you avoid walking a fragile build into the section full of the one thing it cannot handle. Taken home they are ordinary banners again.

They attach to the underside of a block rather than to a wall, which catches people who expect normal furniture rules. Platforms work too, though older versions wanted the platform hammered down into its bottom position first. Which way the design faces is decided by the world column you place it in and nothing else, so if one points the wrong way, take it down and move it a single tile sideways.

The War Table Banner from the event drop is the only one two tiles wide, so it will not sit in a row with the others without leaving a gap. The Gravity Banner from floating islands is a near copy of the Gravitation Potion buff icon, which makes it a readable label if you keep a potion room.

The original four take fairly open cues from the four Hogwarts house animals, down to the lion and the snake. Whoever drew the yellow one gave the badger antlers. The two newer colors arrived much later and carry no such reference.