Gohan could be an interesting character to pair with Goku Black. Gohan has his own unique power and a different approach to fighting compared to Goku. Their interaction could bring out new aspects of both characters. And, from the Bleach universe, Ichigo could be paired with Goku Black. Ichigo's sword - fighting skills and his Hollow powers combined with Goku Black's abilities would lead to some epic battles.
Vegeta would be a great choice. Their rivalry in the original Dragon Ball series could be taken to a whole new level in a crossover setting. Another good character could be Trunks. Since Goku Black has a connection to Trunks in the main story, it would be interesting to see how they interact in a different scenario.
Trunks is another good option. His time - traveling experience and sword - fighting skills could add a new dimension to the crossover. He and Xeno Goku could work together to prevent disasters in different timelines.
Vegeta. Since they have a long - standing rivalry in the Dragon Ball series, a crossover where they have to team up against a greater threat would be great. They could learn to work together better while still maintaining their competitive banter.
Luffy from One Piece could also work well. Luffy's carefree and optimistic nature against Gajeel's more serious and gruff personality would create an interesting dynamic. Maybe they're on a quest to find a powerful treasure in a new world created by the crossover.
Superman could be paired with Obito in a crossover. Superman's pure - heartedness and incredible powers could influence Obito. They could work together to protect a city under threat. Obito might be in awe of Superman's abilities at first but then find ways to contribute with his ninja techniques.
In a crossover with the Fate series, Saber could be paired with Toguro. Saber's sense of honor and her noble fighting style would clash with Toguro's brute force and underhanded tactics. It would create a really interesting dynamic, whether they are on opposing sides or forced to work together for some greater purpose.
In a crossover with the Naruto universe, Sasuke could be a great character to pair with Illumi. Both are somewhat dark - natured and highly skilled. They could start off as enemies, with Illumi seeing Sasuke as a target or a rival in power, but then gradually develop an understanding or a strange alliance as they realize they have common goals in terms of seeking power and revenge in their own ways.
Hit would also make for a fascinating pairing. Hit is a skilled assassin with time - manipulation abilities. He could be a great foil to Goku Black. Maybe Goku Black tries to outwit Hit in his time - stop techniques, or they could form a temporary alliance based on their mutual desire to eliminate certain opponents in the tournament. There would be a lot of cat - and - mouse action between them.
The Punisher would be a great character to pair with Rorschach. Both are anti - heroes who take extreme measures to combat crime. They could have an interesting dynamic, debating the morality of their actions while on a mission to take down a powerful criminal syndicate.
In a crossover with 'One Piece', Blackbeard would be an interesting character to pair with evil Kaneki. Both are complex and morally ambiguous characters. Blackbeard's thirst for power and his ability to manipulate situations could be enhanced by Kaneki's ghoul powers. In the 'Fairy Tail' universe, Jellal could be a good match. Jellal has his own dark past and his powerful magic could interact in an exciting way with Kaneki's kagune. They could either be rivals or form an uneasy alliance.
Lara Croft would be an interesting character to pair with Handsome Jack. She's a strong - willed and adventurous archaeologist, and her no - nonsense attitude would contrast with Jack's over - the - top personality. Their interactions could involve Jack trying to steal some ancient artifact that Lara is protecting, leading to a battle of wits and skills.