He could have the power of telekinesis like Goodwitch. This would allow him to move objects with his mind, which would be useful in combat against Grimm. He might also be able to create force fields to protect himself and his allies.
One possible plot could be that Glynda's son discovers he has unique powers, different from his mother's. He struggles to control them while also trying to fit in at Beacon Academy. Maybe he has to deal with the expectations of being Glynda Goodwitch's son.
Well, the story could be about the son inheriting Goodwitch's magical abilities. He might grow up in the world of RWBY, facing the same threats as the main characters. Maybe he would attend Beacon Academy and form his own team, using his mother's teachings and his unique powers to fight against Grimm.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of RWBY fanfictions. Just search for 'Glynda Goodwitch son' in the RWBY section, and you might find some interesting stories.
He could have the power of light. Maybe he could create blinding flashes to disorient his enemies. Also, he might be able to control the sun's heat, using it in combat like shooting out beams of intense heat.
One possible plot could be that Naruto, as Glynda's son, grows up in a world that combines the elements of the Naruto universe and the world where Glynda exists. He might inherit some of her magical abilities along with his own ninja skills. For example, he could use chakra to enhance his magic or vice versa. He may face challenges in both worlds, having to deal with ninja enemies as well as magical foes. Maybe he has to hide his dual nature from some who might not accept a being with both ninja and magical powers.
One possibility is that Ruby would grow up with a very different set of skills. Goodwitch is known for her strict and proper teaching methods. Ruby might be more refined in her combat techniques and have a deeper understanding of magic. For example, she could combine her scythe - wielding skills with more magical elements, like creating magical barriers while attacking.
She is often depicted as highly skilled in combat and magic. Her semblance, which allows her to manipulate objects with great precision, is a big part of her character in fanfiction. Writers may explore how she uses this ability in different situations, like in battles against Grimm or in training exercises with the students.
He might have the power of earth manipulation. Since Rhea is associated with the earth, Percy could gain the ability to control the ground, like creating earthquakes or forming barriers made of stone. This would be a very powerful addition to his existing powers.
Since Yoruichi has strong spiritual energy in her world, Naruto might inherit some form of enhanced chakra that has spiritual aspects to it. This could give him new jutsu or abilities that are a blend of his original ninja skills and this new spiritual - chakra power. For example, he could use his new power to sense things in a different way, like Yoruichi can sense spiritual presences.
In this fanfiction scenario, Naruto would inherit a host of Saiyan powers on top of his ninja skills. For starters, he would have the Saiyan's natural fighting instincts and the ability to quickly recover from injuries. His power level would constantly increase as he fought, similar to how Saiyans get stronger through battles. His existing jutsus like the Rasenshuriken could be infused with Saiyan energy, making it not only cut through opponents but also blast them with a powerful ki - like force. And with his Saiyan tail, if he had one, he might have an additional form or power that was unique to him, perhaps something that combined the power of the Great Ape form with his Nine - Tailed Fox form.