Chlorophyte Bar

Almost every meaningful upgrade after the mechanical bosses runs through this material, whichever class you are playing. The armor alone justifies the farm, and the same stock feeds the mining tool that makes the rest of the world trivial and the ghost-tier bars that come later. Get the farm running before you fight Plantera, not after.

The ore creeps through jungle mud on its own, so a chunk of jungle left intact is a renewable crop rather than a vein that runs dry. Smelted bars lose that behavior entirely, so a chest full of them is inert. If you want a supply that keeps growing, leave ore in the ground and only smelt what you are about to spend.

Chlorophyll plus the usual mineral ending. The green algae division chlorophyta lands in the same place. The brown handles on the tools made from it are presumably jungle mahogany, since both come out of the same biome.