Ultra Instinct is the ultimate martial arts technique Dragon Ball franchise. Known far and wide as the natural state of being for the angels of the multiverse, this fabled technique is notoriously difficult for anyone outside of this powerful race to learn, even as powerful as the Gods of Destruction.
The main reason this is such an elusive concept is that it requires the user to be in a completely calm and stable state of mind, allowing their body to react to danger on its own. Even though Goku is the only person in the Dragon Ball aside from the angels who were able to fully utilize it, some characters would be perfect candidates to eventually unlock it for themselves.

Dragon Ball: The 8 Most Powerful God Technique Users, Ranked
God Techniques are the most powerful techniques in the Dragon Ball multiverse, and these users are particularly terrifying and dangerous.
5
Gohan could potentially unlock this technique
A separate path to power
After the Tournament of Power and Granolah arcs, fans were convinced that it was only a matter of time before Gohan unlocked Ultra Instinct. Although his incredible Beast form was what fans got instead, a significant number of fans believe that this may still be possible in the future.
While it's unlikely, no one would be wrong to assume a connection between Gohan and Ultra Instinct from a basic perspective. Since Ultra Instinct requires calmness and control above all else, Gohan is well-suited for this technique due to the restraint he has shown against powerful villains, as well as his cerebral nature.
4
Master Roshi seems to already have mastered this technique
Goku's legendary teacher
It's safe to say that Goku wouldn't have gotten anywhere near where he is without the direct influence of Master Roshi, who is known as one of the greatest martial artists in the universe. Although his strength was already impressive, the real reason why he is a prime candidate for learning Ultra Instinct is because he already had something quite similar.
Whis noted that the most important thing one needed to master this technique was a calm heart and mind so that the user could fully immerse themselves in the battle. Although far past his prime, Roshi's calm nature allowed him to instinctively dodge a barrage of attacks from Jiren, making him the closest mortal to achieving Ultra Instinct after Goku himself.
New questions added!
GameRant Quiz
Start
3
Uub is a great candidate for achieving ultra instinct
Latent power plant
As the human and pure reincarnation of Kid Buu, Uub was born at Goku's wish at the end of the Buu Saga. As such, he is also the recipient of an immense amount of Divine Energy that he gained from when the Great Supreme Kai was absorbed by Majin Buu. Because of this, many think he is the perfect candidate to achieve Ultra Instinct.
IN Dragon BallHuman characters haven't been significant for a while now, except maybe Krillin. Since Ultra Instinct is more of a technique than a species-specific transformation, this would make Uuba the perfect person to wield alongside Goku, especially considering his immense latent power as the reincarnation of Kid Buu and the well of Divine Ki he already possesses.
2
Jiren would make an amazing Ultra Instinct user
Universe 11's Greatest Warrior
Out of everyone on this list, it's very likely that Jiren will have already unlocked Ultra Instinct when we next meet him. The main reason is that his composure in battle and unmatched Ki control make him an obvious choice for someone capable of unlocking this technique.
Furthermore, his battle against Goku at the end of the Tournament of Power Arc showed him the power of the technique and that it is possible for even a mortal to learn it, so it is very likely that he has been training tirelessly since the tournament to achieve even greater power with Ultra Instinct. This would make it the best way to reintroduce Jiren into the story.

Dragon Ball: 5 Strongest Broly Techniques, Ranked
Broly is the Saiyan with the most potential of them all, so here is a list of his most dangerous and powerful techniques.
1
Beerus can already use the base version of Ultra Instinct
The most powerful destroyer
It probably won't come as a surprise that Beerus is the closest to getting this technique and has actually already shown the ability to use it. During the Destroyer exhibition match, all the Gods of Destruction simultaneously jumped on Beerus, but he managed to defeat them all thanks to his strength, tactical brilliance, and use of Ultra Instinct.
However, it is true that his use of the technique is very basic, as he uses it in his Ultra Instinct Omen state, surpassing even Goku. Still, using it shows that he already has the aptitude, so it's only a matter of time before he can master it and use it fully to become the most powerful being in the multiverse.
Dragon Ball Super can be streamed on Crunchyroll.