Well, Naruto's Rasengan could be combined with Starfire's starbolts. For example, Naruto could use his chakra control to shape Starfire's energy into a Rasengan - like attack.
Imagine a battle scene where Spiderman's agility and quick reflexes allow him to dodge attacks and get close to the enemy. Then, Starfire uses her powers to stun the enemy with a blast of energy. Spiderman can then use his webs to immobilize the stunned foe. Their powers work in a complementary way, with Spiderman's more street - level powers enhancing Starfire's more cosmic - level powers and vice versa.
Their powers could combine in a really cool way. Harry's magic could enhance Starfire's energy blasts. For example, he could cast a spell on her hands that would make her energy blasts more powerful or more accurate. On the other hand, Starfire's superhuman strength could help Harry in physical combat situations. If they were surrounded by enemies, Starfire could use her strength to clear a path while Harry used his magic to hold off any attackers from a distance.
The origin of Naruto's starfire powers in fanfiction might be due to an experiment. Some rogue ninja or a secret organization could have been conducting experiments with celestial energy. Naruto somehow gets caught in one of these experiments and as a result, he gains the starfire powers. Another possibility is that it's a gift from the stars themselves. Naruto has always been a special character, and the stars, seeing his potential and pure heart, decide to grant him these powers to help him on his journey.
Well, if Naruto had starfire powers in fanfiction, he could probably use it to enhance his existing jutsu. For example, his Rasengan might be infused with starfire energy, making it more powerful and having additional effects like burning or blinding opponents. Also, it could change his battle strategies as he'd have a new and different type of power to rely on.
In fanfiction, perhaps Starfire's alien physiology could be used to enhance Harry's magic. Her unique body chemistry might react with magic in a way that gives Harry access to new spells or a stronger connection to magic. On the other hand, Harry could teach Starfire some basic magic, like levitation, and she could combine it with her natural powers to create a new form of combat or movement. They could also work together to create a magical - energy shield, with Harry providing the magical framework and Starfire supplying the energy.
Rimuru Tempest has a wide range of powers. One of his main abilities is the power of Gluttony. This allows him to devour almost anything and gain knowledge or abilities from it. For example, he can devour monsters and acquire their skills, which makes him extremely versatile in combat.
A common power in fanfiction is enhanced magical senses. Characters can sense magic from far away, like being able to detect a hidden magical artifact from miles away just by the faint magical aura it emits. This helps in treasure - hunting type of storylines.
Loki, the God of Stories, has the power of shape-shifting and can assume various forms. He's also highly intelligent and skilled at deception and manipulation.
Well, their child might inherit Naruto's chakra control and Shion's unique spiritual powers. Maybe the child could have an enhanced form of the Rasengan, combined with Shion's ability to predict the future in a battle sense. For example, being able to foresee an opponent's moves just a split second before they make them and using that knowledge to adjust the Rasengan's trajectory for a more powerful and accurate attack.