Frozen Chest

Each one holds a single main prize with the occasional extra piled on top, and the filler depends on the depth you found it at. Below the surface the usual torches are swapped for ice torches, which is the torch you want burning in the snow anyway since matching the biome nudges your luck up.

Down at cavern depth the chest can hold a Deer Thing, the summon for Deerclops. That replaces the usual chance at an early boss summon in other cavern chests. If you want that fight early, or want to farm it repeatedly, cracking frozen chests deep in the ice is cheaper than gathering the ingredients yourself.