They would most likely meet Goku. Since Goku is an important figure on Earth and has Saiyan heritage himself. It would be interesting to see how Bardock and Gine interact with their son who was raised on Earth.
Krillin is another character they might come across. He is one of Goku's closest friends. His different fighting style compared to the Saiyans could lead to some interesting interactions. He could also teach them about Earth - style martial arts while they show him some Saiyan - based moves.
Well, one possibility is that they could be on a mission to save Earth from some unknown threat. Maybe they discover a new form of evil that the Z - fighters on Earth are not yet aware of, and they use their Saiyan powers to fight it off.
The wizard Gandalf would be an obvious character for Harry to interact with. They are both wizards, though from different worlds. They could share their knowledge of magic, and Gandalf could guide Harry in the ways of Middle Earth while Harry could introduce some new magical concepts to Gandalf.
Goku is often paired with Gine in fanfiction, as their mother - son relationship can be explored in different ways. Bardock is also a common pairing since he was her husband in the original lore.
Naruto could meet some young and upcoming Iwa ninja trainees. They might be curious about Naruto and his abilities from Konoha. These trainees could either look up to Naruto or be jealous of his fame, leading to various interactions. Also, there could be some old - timer Iwa ninjas who remember past events involving Konoha and have their own views on Naruto's presence in Iwa.
There's a possibility that Naruto meets some of the younger generation of shinobi in Suna. These new characters could be eager to learn from Naruto or challenge him to a friendly spar. He may also come across some of the elders in Suna who have their own stories and wisdom to share with Naruto.
She might meet Aro, one of the leaders of the Volturi.
Maybe he'll encounter a young genius student who becomes his sidekick for the time he's at school. This student could help him with his high - tech gadgets or offer unique insights into the school's problems. Also, he might run into the principal who is initially suspicious of him but later realizes his good intentions.
In this fanfiction, Harry might meet students from various backgrounds. There could be students from far - off magical lands who have their own unique cultures and magic. He could also run into some Beubaxtons alumni who come back to visit and they might share some interesting stories or give him some advice on how to make the most of his time at Beubaxtons.
He could meet his future self. This would be a very interesting encounter as he could learn from his future self about what he has accomplished and what mistakes he should avoid. He might also meet the future generations of his family, like his grandchildren or great - grandchildren.
He will surely meet the Black Panther. It's Wakanda after all.