One Piece: Heart of Gold
A girl named Olga is pursued by both the World Government and a man named Mad Treasure, as she is the only one who knows the location of the Pure Gold, a substance that can buy the entire world. Olga ends up sailing with the Straw Hat Pirates, and they journey to find the Pure Gold on the lost island of Alchemi, which is located inside the stomach of a large angler fish named Bonbori. (Source: IMDb)
Seasons
One Piece Special: Adventure in the Ocean's Navel
One Piece Special: Open Upon the Great Sea! A Father's Huge, HUGE Dream!
One Piece Special: Protect! The Last Great Performance
One Piece Special: The Detective Memoirs of Chief Straw Hat Luffy
One Piece: Episode of Nami - Tears of a Navigator and the Bonds of Friends
One Piece: Episode of Luffy - Hand Island Adventure
One Piece: Episode of Merry - The Tale of One More Friend
One Piece 3D2Y: 15th Anniversary
One Piece: Episode of Sabo - The Three Brothers' Bond
One Piece: Adventure of Nebulandia
One Piece: Heart of Gold
One Piece: Episode of East Blue
One Piece: Episode of Skypiea
One Piece: Barto's Secret Room