The Gura Gura no Mi is considered the strongest Paramecia
Logia. The rarest and most powerful of the three Devil Fruit types, Logia-type Devil Fruits allow their users to create, control, and transform their body into a natural element, such as sand, mud, smoke, lightning, plant life, and even darkness.
The Supa Supa no Mi is a Paramecia-type Devil Fruit that enables the user's body to gain characteristics of a steel blade to attack opponents with, making the user a Fullbody Bladed Human (全身刃物人間, Zenshin Hamono Ningen?, VIZ: "Human Sword"). It was eaten by Daz Bonez, also known by his Baroque Works alias Mr. 1.
The Ope Ope no Mi is the most versatile devil fruit in the One Piece world. This Paramecia-type devil fruit allows the user to create a dome space called “Room,” and the user can freely manipulate any person or thing inside this room like a surgeon. This devil fruit can also cure untreatable diseases.
The Inu Inu no Mi, Model: Okuchi no Makami is a powerful Mythical Zoan type of Devil Fruit that was introduced to the fans towards the end of the Wano Country arc. This legendary devil fruit is precious and was in possession of Kaido of the Four Emperors for quite a long time.
The Soku Soku no Mi is a Paramecia-Type Devil Fruit that enables the user the ability to move at extreme speeds, thus making the user a Fast Human (速い人間 Hayai Ningen).
As mentioned above, there are four gods in One Piece namely the Sun God, Rain God, Forest God, and Earth God. Although it was revealed that Luffy's Devil Fruit gave him the powers of the Sun God Nika, the identities of other characters with godlike powers are still a mystery.
One Piece shows a new awakening of a Zoan-type Devil Fruit, confirming that Luffy's version of this rare and powerful ability is absolutely unique.
While a part of this can be attributed to his extremely notorious crew, Blackbeard has another ace up his sleeve: he is the only confirmed character in the entire series to possess the power of two Devil Fruits.
Luffy has only eaten one Devil Fruit the Gomu Gomu no mi which turned him into a rubber man. Fairly recently, it has been revealed to actually be the Hito Hito no mi (Model Nika) which grants him the powers of the Sun God Nika in ancient times.
Finally, the Wano country arc of One Piece explained the concept of Devil Fruit Awakening to the fans when Luffy finally managed to awaken his Gomu Gomu no Mi. It was revealed to the fans that his Devil Fruit was actually the Hito Hito no Mi, Model: Nika, and went by a different name to hide its true powers.
Hito Hito no Mi, or human human fruit, is a zoan type devil fruit. This fruit's effects on humans are unnoticeable because the effect itself is turning the user into a human. If Sanji ate this fruit, the only ability he would gain is a swimming disability.
In a Water 7 filler episode, Sanji finds another hint of the All Blue's existence. Salt is brought by the Aqua Laguna from all the seas and Sanji compares it to the All Blue. It is shown to be such a good seasoning that a small amount in food is enough to outclass even his own cooking.
In fact, Nami has already demonstrated abilities similar to Haki. During the Alabasta Saga, she has shown the ability to tell even the slightest of changes in weather which, according to Vivi, is beyond human comprehension.
It is widely known that each Devil Fruit is unique and, as long as its user is alive, there cannot exist another with the same ability in the world.
The Katana Katana no Mi is a devil fruit that gives the user the ability to summon up a Katana. This Katana however is formed from the very soul of the user. This means that the blade is the user and the body is the blade.
2 Magu Magu no Mi
As a Devil Fruit that has shown no clear weakness, the Magu Magu no Mi is perhaps one of the strongest.
One of the many snake Fruits seen in One Piece, the Yamata no Orochi version is considered to be the rarest out of them all. It was eaten by the Shogun of Wano, Kurozumi Orochi, and it grants him the ability to transform into an eight-headed serpent, each head having its own personality.
Although not considered to be the strongest of Devil Fruits, the Gomu Gomu no Mi is quite a unique power and just like most other Devil Fruits in the story, it has its own set of strengths and weaknesses.