He might gain Minato's teleportation jutsu. It was one of Minato's signature moves, and with Minato sealed in him, Naruto could potentially access and learn this powerful technique.
Naruto could potentially gain enhanced speed and reflexes. Minato was known for his incredible speed. If sealed within Naruto, some of that speed could transfer to Naruto, making him even more formidable in combat. Also, Minato was very intelligent when it came to battle strategies. Naruto might inherit this strategic thinking ability, allowing him to outwit his opponents more easily.
He might gain some of Madara's Sharingan - related abilities. Maybe he could use some of the advanced genjutsu techniques that Madara was proficient in. Since Madara had strong chakra, Naruto could also potentially have an increase in his own chakra levels or a new way to manipulate chakra, like Madara's ability to control the Susanoo.
He might gain the ability to use his parents' chakra more directly. For example, if his father was good at a certain type of jutsu, Naruto could potentially access that more easily. Maybe some kind of enhanced speed or strength that was unique to his father.
If Naruto became an Ino fan due to Kyuubi's influence, he might gain some mental fortitude. Ino is good at mind - related jutsu, and Naruto could learn from her how to better protect his mind from enemy attacks. Maybe he'd start to develop a form of mental shielding similar to Ino's techniques.
He could potentially gain an enhanced understanding of wood - style techniques. Since Hashirama was a master of it, Naruto might learn how to create more complex and powerful wood constructs, like huge forests for both offense and defense.
Naruto might be able to create cloud - based illusions. Just as he can create shadow clones, with the power of Cloud sealed in him, he could project illusions made of clouds to deceive his opponents. These illusions could be large - scale and very realistic, confusing enemies about his true location and intentions.
Well, Naruto might develop a jutsu that taps into Shukaku's unique chakra nature. Since Shukaku is associated with sand, he could create a jutsu where he encases his opponents in sand - infused with his own chakra, immobilizing them. Also, given his creativity with jutsu, he could come up with a way to use Shukaku's energy to boost his Rasengan. For example, a Sand - Rasengan that has the added density and power of Shukaku's sand.
He could potentially gain some form of Sharingan - like ability. Since the Sharingan is a signature Uchiha power, it makes sense that if Naruto were acting like an Uchiha, he'd develop something similar. Maybe a version of it that combines with his own Uzumaki chakra, creating a unique and powerful new ability. He might also gain better control over fire - based jutsu, as the Uchihas are often associated with fire. And perhaps enhanced perception skills, which are also characteristics of the Sharingan.
He could gain the power of manipulation. Gaster might give Naruto the ability to manipulate space or time on a small scale. Maybe he could create small portals or slow down time for a short period during combat.
He could gain the ability to create large - scale wooden structures, like Hashirama did. For instance, he could build huge wooden golems to fight for him in battles.
Naruto could potentially gain the power of omnipotence. Since the Infinity Stones are extremely powerful in the Marvel universe, in the Naruto fanfiction, they could give Naruto abilities beyond imagination. He might be able to use the Stones together to rewrite the rules of the ninja world. For example, he could make chakra obsolete and introduce a new form of energy using the combined powers of the Stones. Also, he could use the Power Stone to boost the power of his Rasengan to an unimaginable level, capable of destroying entire mountains with a single throw.