Wally West's powers come from a unique set of circumstances. It involves a scientific mishap that leads to his contact with the Speed Force, granting him the amazing speed and other related powers that define his character in the comics.
Another way Ichigo could get his powers back in fanfiction is through a magical or spiritual artifact. Maybe he discovers an ancient sword or a talisman that has the ability to restore his lost powers. This could be part of a grander plot where he has to go on a quest to find this item, facing various challenges and enemies along the way. During this journey, he might also learn more about the true nature of his powers and how they are connected to the overall 'Bleach' universe.
One unique way in fanfiction is that he gets his powers from a virtual reality experiment. The scientists were trying to simulate the powers of a spider in a digital realm, but something went wrong and Peter Parker, who was a test subject, got the powers transferred to him in the real world.
One way could be through a magical encounter. Maybe he stumbles upon an ancient artifact that has the power to restore his abilities. It could be a relic from his home planet that he discovers by chance.
His powers would change a great deal. Naruto is known for his brute strength and his ability to never give up. The Sharingan would add a whole new layer of finesse to his fighting style. He could use the Sharingan's genjutsu capabilities to trap his enemies in illusions before hitting them with a powerful chakra - infused punch. Also, he could use it to analyze his opponents' weaknesses more quickly, allowing him to adapt his fighting strategy on the fly.
His relationship with Sakura might change. Sakura would be even more impressed with Naruto having this new power. She might see him as an even greater ninja and could potentially develop stronger feelings for him. Naruto, on the other hand, might use his telekinesis to do small things for Sakura, like picking flowers for her without having to touch them.
There are specific storylines within the New 52 Flash series where Wally gets powers. These often involve complex plot developments and encounters with powerful forces.
Another possibility is that one of Leo's classmates becomes jealous of his powers. This classmate could start spreading rumors about Leo, trying to turn everyone against him. Eventually, the jealousy could turn into something more sinister, and the classmate could team up with some bad elements to try and take away Leo's powers.
Rocket could be another helper. With his technical expertise, he could build a device or figure out a scientific solution to bring back Peter's powers. He's always been good at tinkering with things.