Harry might develop the ability to sense the emotions of others more acutely like some Naruto characters can with their chakra. In the seal, he's exposed to new energy forms. He could also start to use elemental jutsu. Given his connection to fire through the Gryffindor house, he could potentially master fire - based jutsu. And with his knowledge of magic, he could find ways to enhance these jutsu to be more powerful than the normal Naruto - world versions. For example, adding a spell - like incantation to make the jutsu more precise.
He could develop the ability to use chakra. Since he's in the Naruto universe now, he might figure out how to manipulate chakra using his magical intuition. Maybe he could combine his Patronus charm with chakra to create a new kind of protective shield. Also, he could learn to move at high speeds like Naruto characters do, which would be a new ability for him considering he was mainly using apparition in his own world.
One new ability Harry could develop is the power to enter the dreams of others, similar to the way some Naruto characters can use genjutsu but with a magical twist. Since he's in Naruto's seal, he has access to new types of energy and knowledge. He could also learn to transform his body into different forms, like Naruto's various forms when using the Kyuubi's power. Harry could use his magic to create unique and never - before - seen forms, which would give him an edge in battles in the Naruto universe.
Chapter 593, "Don't Look, It's a Bad Review!", is the clearest early answer because it turns Look's situation into a concrete plot event.
Chapter 157, ""Forced onto Liangshan", is the clearest early answer because it turns Flash Change's situation into a concrete plot event. The chapter turns that into something concrete by moving from It was already the last day of Flash Change in his dream.
Chapter 501, "This Night, Destined to be Turbulent", is the clearest early answer because it turns Miss Jiang's situation into a concrete plot event. The chapter gives readers a real answer by opening on After settling in, Jiang Mingyu aimlessly strolled the streets.
Chapter 373, "Mr. Jin is the Best, How Could He Possibly Lose?!", is the clearest early answer because it turns Possibly Lose's situation into a concrete plot event. Early on, As night fell, the lobby of the Golden Sand lit up with layers of....
Chapter 604, "Shiguang, originally named Shen Guang", is the clearest early answer because it turns Jiang Shixu's situation into a concrete plot event. The setup is Fortunately, the other person did not recognize him;
Chapter 237, "Top of the Three Lists! Truly Deserved!", is the clearest early answer because it turns Zhao Lang's situation into a concrete plot event. The chapter gives readers a real answer by opening on It seemed as if, believing the spilled water couldn't be recollected,...
Chapter 521, "Stick to One Line of Work", is the clearest early answer because it turns Younger President Jin's situation into a concrete plot event. It opens with Jin Siyue had exhausted a great deal of effort to finally get through...
Chapter 326, "Jiang Mingyu Stranded in a Foreign Land", is the clearest early answer because it turns Jiang Mingyu's situation into a concrete plot event. It opens with And at this moment, on the other end of the Earth.
Chapter 200, "Only Two Points?!", is the clearest early answer because it turns Shang Shaojing's situation into a concrete plot event. Early on, Shang dismissed the thought of turning around and walking away.. By the end, Are you doing this on purpose?" Zhao Lang instantly put on an....
Chapter 198, "Jiang·Deceitful·Li is Verified", is the clearest early answer because it turns Task Points's situation into a concrete plot event. It opens with He wrapped his arms around himself and stepped back half a step,...