5 Strongest Non-Canon Villains in One Piece

BEAR KING

Bear King is the main antagonist of Movie 2, and the leader of the Trump Siblings Pirate Crew that ruled over Clockwork Island.
Bear King has eaten the  Kachi Kachi no Mi Devil Fruit, which allows his body to become hard as rock to augment his defenses, as well as letting his strikes hit harder. Another effect of his Devil Fruit is that it allows him to heat up his fist, and possibly other parts of his body, at will, which will serve to burn his opponents on contact.

ZEPHYR

“Black Arm” Zephyr, was the leader of the Neo Marines and the main antagonist of One Piece Film: Z. He was once a Marine admiral and instructor before his resignation.
Alongside Garp, Sengoku, and Tsuru, Z was one of the most powerful Marines of his generation. Despite his old age, Zephyr had tremendous physical prowess.
He mastered Busoshoku Haki at the age of 34, allowing him to coat himself with it and turn his arms black for much more devastating strikes and defenses, which earned him the nickname “Black Arm”.
He was able go toe to toe with Admiral Kizaru several times, and later showed extraordinary stamina by stalling Kizaru, several vice admirals and an entire battalion by himself — all without the Battle Smasher — before ultimately dying in the battle.

BYRNNDI WORLD

Byrnndi World is the captain of the World Pirates and the main antagonist of the 3D2Y anime special.
World is a very powerful pirate, as he was held in Level 6 of Impel Down and escaped, which was thought to be near impossible. He had a 500,000,000 Berries bounty, which testifies how large of a threat World was according to the World Government. Despite his age, he remains a world-class threat.
World ate the Moa Moa no Mi, a Paramecia-class Devil Fruit that allows him to increase the speed and size of objects. He typically uses this to increase the size and velocity of projectiles, increasing damage, as well as boosting his own already powerful speed to higher levels.
He is very skilled in using Busoshoku Haki.

GILDO TESORO

Gild Tesoro is the main antagonist of One Piece Film: Gold. He was formerly the Casino King, and the proprietor of Gran Tesoro, the largest entertainment city-ship in the world, before his defeat and arrest.
Tesoro ate the Gol Gol no Mi, which allows him to manipulate gold he has touched at will. He can use this power to create huge fountains of liquid gold, trap his enemies, and infuse gold dust and flakes into other people’s bodies so that he can then slowly transform their skin into gold. He is also able to create gold armor that grants increased power and defense. He can manipulate it to the extent that he can create and pilot a massive golden golem, the size of a skyscraper. His gold is strong enough to withstand a slash from Zoro’s swords.
Since consuming his Devil Fruit he has been able to awaken its powers, furthering the range of his influence over gold. When utilizing large gold constructs he is also capable of unleashing focused light beams or explosive force through unknown means that have the power to destroy a Marine warship or critically injure an opponent with a single blow.

SHIKI THE LION

Shiki the Golden Lion is the admiral of the Golden Lion Pirates and the first prisoner ever to escape from Impel Down.
He wreaked havoc on the seas during Roger’s time and is the main antagonist of Movie 10.
Alongside Roger and Whitebeard, Shiki is one of the most powerful pirates of his generation. He has tremendous physical strength supplemented with his supreme sword skills, allowing him to slay an army of Marines at Marineford, and it took the combined efforts of both Garp and Sengoku to subdue him with the conclusion of their fight leaving half of Marineford destroyed.
Shiki ate the Fuwa Fuwa no Mi, a Paramecia type Devil Fruit which allows him to make surrounding non-living matter levitate once he has come in contact with it.
When attacking, Shiki uses the surrounding environment against his enemies, shaping earth or snow into giant lion heads and launching them towards his foes, or even making water float to drown his opponents in it. As stated, his powers are unable to be used on any living matter other than himself, meaning he cannot touch another person, animal, or plant and make them levitate.