The world of One Piece is one whose aesthetic can only be described as if Pee-Wee's Playhouse wanted to fight someone. At the heart of the world's magic systems is its beloved Devil Fruits, a strand of not-so-delicious plant life who can grant their users incredible powers at a single bite but at the sacrifice of their swimming ability.
With them, anything (even inanimate objects) have been known to control the elements, transform into magnificent animals, and whatever being a Paramecia means. Despite a lot of people in the series already having Devil Fruits, there's still plenty more room in the club, with the next Devil Fruit user only limited by their proximity to a fruit bowl. This list will be looking at some of the series' more human characters (relatively speaking), as it ascertains who is a future Devil Fruit user.
9 Bepo
Bepo as a character already has a lot going for him. He is the brother to Zepo, an old member of the Nox Pirates and the deceased partner to Pedro, and the entrusted navigator and essentially first mate of the Heart Pirates. As a member of the Mink Tribe, he is a humanoid mammal who's assumedly capable of the Mink electro as well as their beastly strength.
He also appears plenty adept at kung fu. As talented and varied as he is, he is still considered one of the weaker characters within the grand scope of the Grand Line and, as the trusted second to Trafalgar Law, could use the extra insurance policy of having a Devil Fruit, possibly one that can improve upon his map drawing skills.
8 Franky
Cyborg Franky is the eccentric engineer and shipwright of the Straw Hat pirates whose imagination seemingly has no bounds for innovation. Knowing that it does make sense that the man known as "Cyborg" has increasingly less regard for the sanctity of his own body.
As a pervert and kid who should've died long ago, Franky has been incredibly cavalier about giving his body a variety of changes and improvements. The prospect of a Devil Fruit must be incredibly tantalizing to a man who dedicated an entire button on his body to just changing his hairstyle.
7 Nami
Nami is a tough cookie in this instance. While she is a human character, she already possesses great abilities with her Clima-Tact, a wondrous device that grants her weather bending abilities that already rival Devil Fruit abilities. However, as powerful as this has been, Nami has shown time and again that she is no more invulnerable and prepared for the dangers of the New World as she was before the time skip.
She may be a better navigator, but Nami still seems all too insignificant to the world changing and destroying figures that line the armies of the Emperors. As someone who could also use a Devil Fruit to shake more money from her opponents and shipmates, Nami would probably be open to the decadence of a Devil Fruit.
6 Jesus Burgess
Jesus Burgess is the helmsman and most active fighter (whether Teach likes it or not) of the Blackbeard Pirates. He's used his own natural strength to take on a variety of strong fighters, going as far as to single-handedly dominate his block in the Corrida Colosseum. It is during that time on Dressrosa that Burgess has expressed a clear interest in getting his own Devil Fruit.
With it, his already incredible strength would be significantly multiplied. He could not only be a more terrifying champion but also possibly exact revenge (if he hasn't already) on the Revolutionary Chief-of-Staff, Sabo.
5 Vivi
There's a lot riding on Princess Vivi's shoulders. As the heir to the Alabasta Kingdom, an outspoken figure for peace over war, and a possible target of the hidden, higher-ups of the World Government, Vivi is a defining voice in the world whose capacity to invoke real change kind of hinges on her own personal ability to not die.
While she did seem to be a capable agent in Baroque Works, there are obviously greater and more overwhelming dangers that could be hiding in her streets and even her walls. As one of the most important princesses and a beloved fan favorite, Vivi, more than ever, needs the crazy powers capable of handling the crazy world before her.
4 Capone Pez
While the next generation of pirates is already drawing near, it's never too early to think of the distant generations of villainy to come. One of the most promising figures that may come of it is Capone Pez, the baby boy of Capone "Gang" Bege and Charlotte Chiffon. As the heir for Bege's empire of destruction, Pez already has a vast army and armory waiting for him.
However, he also has Big Mom's DNA running through him, meaning that destructive, hungry energy could also be sneaking up on future generations. It only makes sense that, given his bloodline's history with Devil Fruits and destructive power, Pez would be a clear candidate for the forbidden fruit.
3 Makino's Baby
On the note of the future generation of brutes and adventurers, if the rumors about Makino and Shanks are true, then Makino's baby has a really promising future in the One Piece world. It is a rarity in the One Piece world that the offspring of pirates don't, in turn, also become pirates.
And with a possible, not confirmed (but essentially confirmed) father in Shanks, Makino's baby is held at a higher pedestal to be an exciting and powerful adventurer of the sea. To give the young gun a special, Luffy-esque head start, it would be hilarious if the child were to also accidentally eat a Devil Fruit under Shanks' watch.
2 Tashigi
Tashigi was a promising figure early on in the series. As the doppelganger (possibly amnesiac personality) of Roronoa Zoro's childhood friend Kuina, Tashigi seemed primed to be a threatening rival to Zoro's climb to become the world's greatest swordsmen. Her exact showing, however, has left a lot to be desired.
While not exactly a weakling, Tashigi is far from the highest of the sword fighting ranks, with her greatest feat being deflecting a single cannonball. Zoro's kind of been doing stuff like that since at least Ennies Lobby. As a promising sword fighter and the second to Vice Admiral Smoker, Tashigi is probably gonna get the boost of a Devil Fruit to reassert herself in the conversation.
1 Koby
There's a lot about Koby that just screams that he's gonna get a Devil Fruit power. He was a weakling early on in the series who, with hard work, built himself up in the Marine ranks yet still lags far behind his pirate rival, Luffy. He also aspires to become an Admiral, a league of Marine superpowers who are infamous for their landscape changing, Devil Fruit abilities.
To really boost his role, especially with the final battle and grand finale drawing near, Koby will most likely enter the ending dialogues with a new, fancy Devil Fruit helping him withstand Worst Generation and Emperor alike.