Naruto could potentially gain the ability to access some of Madara's memories. This would give him knowledge about ancient ninja techniques and the history of the Uchiha clan. Also, he might be able to use Madara's space - time ninjutsu, which would be a huge addition to his combat abilities. And, his own Sage Mode could be enhanced by Madara's power, allowing him to be even more powerful in battle.
In this fanfiction scenario, Naruto could gain some extraordinary powers. For one, he might inherit Madara's ability to regenerate quickly, which would make him even more difficult to defeat in combat. He could also gain an understanding of the Uchiha's unique chakra nature and be able to blend it with his own Uzumaki chakra. This could result in new and powerful jutsu that no one has ever seen before. Additionally, Naruto may be able to tap into Madara's battle experience and instincts, making him a more formidable fighter in both one - on - one battles and large - scale warfare.
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 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.
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.
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.
Naruto would gain some really cool (pun intended) new abilities. The ice - making ability would be the most prominent. He could form ice clones, similar to his shadow clones but with the added advantage of being made of ice and potentially having more durability. His sensory abilities might also be enhanced, as Esdeath has a good sense of her surroundings when using her powers. He could detect enemies hidden in the ice or snow. And, like I said before, the time - freezing power. This would allow him to analyze his opponents' moves during the frozen time and come up with the perfect counter - attack. It would add a whole new dimension to his combat skills.
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 could gain the ability to heal in a more advanced way. Just as the avatar can sometimes use their connection to the elements to heal, Naruto might be able to do the same with his chakra. He could also have the power to merge with the natural world around him, similar to how the avatar can connect with nature. This would give him an edge in stealth and surprise attacks. Plus, he could develop a new form of sensing, being able to detect not just chakra but also the energy of the elements around him.
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 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.