Garden Gnome

A placed gnome quietly raises luck for anyone inside a large rectangle around it, the way a Heart Lantern covers a room. There is no icon, no entry in the buff bar, nothing on screen to confirm it is working, and that is the one real annoyance. The workaround is to stick a Campfire or Sunflower next to it and watch for that buff instead. If the campfire icon is up, you are inside the gnome's box too. Extra gnomes add nothing. One per location is the whole story.

Luck feeds drop rolls and spawn rolls, so the spots worth covering are the ones where you repeat something a hundred times: boss arenas, fishing holes, statue farms, biome grinding setups. Blanketing an entire world with them is technically possible, just extremely tedious.

You do not craft these. A Gnome enemy becomes one the moment sunlight reaches it, which means daytime with no wall of any kind behind it, and it will not happen under water. Once it flips, it is furniture forever. Gnomes turn up around Living Trees and favor natural Living Wood Wall, so a hollowed-out Living Tree makes a decent pre-Hardmode farm that pays well in coins on the side. Up and down cycle the placement sprite, including the one mooning the camera, which is a nod to an old internet meme.