Marshal D Teach is the one and only known devil fruit user that have two devil fruit up his arsenal. He doing that by doing some kind of mystery ritual and took the power from a dead devil fruit user. This baffled all aver reader also all character in one piece because stated that this is impossible. He currently have the Yami yami no mi the power of darkness and Gura Gura no mi the power of thunder. As being one of the rare category of devil fruit Pell the Falcon said that its at least 5 known devil fruit user that can take flight ie flying. For example as himself using the power of Tori Tori No Mi falcon to fly. Although there are one technique that non-devil fruit user like sanji has mastered in ordered to fly or float in the air named Sky Walk.
Although there are many devil fruit user some of them hasnt been name yet or at least for now. this is including Eustass Kid that have the power of magnet, Jewelry Bonney that have the power of Youth(not aging), X Drake that have the power of shape shift into dinosaur T rex, Marco that have the power of phoenix regeneration, and others. This leads to a fan made named on this unnamed devil fruit.
In the episode three of this anime. Morgan stated that there are power in one piece world that can turn people into fire and people can make a massive tsunami. Turns out this power belongs to devil fruit user Portgas D Ace using Mera Mera No Mi (fire) and Whitebeard Gura Gura No Mi respectively, And coincidentally both of this user is a Whitebeards pirate and both died at the same war in MarineFort war.
Whenever the writer of this anime wants to includes a devil fruit user into the anime filler, the writer must consult with ist author Oda for confirming. This just simply a yes or no question for Oda, staying that so Oda can choose whether this devil fruit will be in fillers or Oda would want them in the future.