Kraken

This is a dungeon grind, and a long one. Any enemy down there can roll it once Plantera is dead, so the usual approach is a farm room in the post Plantera dungeon that funnels spawns to one spot. Before you build it, know that the roll only happens on enemies that also drop coins, which means a farm running off statues will never produce one no matter how long you leave it going.

No other yoyo throws a body this wide, and the size does real work: a fat projectile clips enemies you were not aiming at and holds contact on something that is trying to circle you. Give it a counterweight and the string upgrade and it carries a melee character through the pillars comfortably, right up until the Terrarian drops and makes every other yoyo pointless.