Well, Naruto joining the Z Fighters would mean a lot of cultural exchange too. Naruto comes from a world with a complex ninja society, and the Z Fighters are from a more science - fiction - like world. Naruto might introduce concepts like chakra control and different ninja clans to the Z Fighters. And the Z Fighters could show Naruto their advanced technology and spaceships. In terms of battles, Naruto's shadow clone jutsu could be used to confuse enemies, while the Z Fighters' super - fast punches and kicks would be a new sight for Naruto. They could learn from each other and become even stronger as a team.
Naruto's chakra - based powers would contrast with the ki - based powers of the Z Fighters. His Rasengan, which is a concentrated form of chakra, could potentially be combined with the energy blasts of the Z Fighters. For example, Goku could add his ki to Naruto's Rasengan to create an even more powerful attack. Also, Naruto's ability to transform, like his Nine - Tails Chakra Mode, would give him an edge in terms of raw power and speed, which could be on par with some of the Super Saiyan forms of the Z Fighters.
A fanfiction might explore Good Broly's relationship with the other Saiyans on Earth. Maybe he starts training with the younger Saiyans like Gohan and Trunks. He could teach them about the raw power of the Saiyans from his own experiences. This would lead to some interesting training sessions and a new bond forming between Broly and the rest of the Z - fighters.
One possible plotline could be that Broly, in his rage, accidentally provokes Beerus. Broly, not knowing who Beerus is, attacks him. Beerus, initially amused, decides to teach Broly a lesson but soon realizes that Broly's power is growing at an alarming rate. This leads to an intense battle where Broly pushes Beerus to use his full power. Another plotline could be that Beerus hears about Broly's power and decides to test him. He travels to Broly's location and challenges him. Broly, seeing Beerus as a threat to his friends or his planet, fights back with all his might.
One possible plotline could be that Cell, seeking to prove his superiority, challenges Broly. Broly, in his usual berserk state, accepts without hesitation. The fight could start with Cell trying out his various attacks like the Kamehameha - like Solar Flare and his physical strikes. But Broly's power is just too much and he starts to overpower Cell. However, Cell then reveals a new, hidden ability that he has been developing in secret and the tables are turned for a while.
A plotline could involve Broly being sent to Kale's universe by some sort of interdimensional rift. Kale initially sees him as a threat and attacks. But as the fight progresses, they start to understand each other's power and motives. Or perhaps a fanfic could have a story where both Broly and Kale are training on the same planet. Their training methods clash, leading to a fight where they both learn from each other and grow stronger in the process.
A plotline could start with Frieza hearing about Broly's power and being jealous. He then devises a plan to ambush Broly. But Broly, being extremely perceptive in his own way, senses Frieza's approach and is ready for the fight. As the fight progresses, Frieza realizes that Broly is much stronger than he expected and has to use all his dirty tricks to try and win. Or perhaps the plotline could involve Broly being captured by Frieza's forces, and then Broly breaks free and goes on a rampage against Frieza and his minions.
Well, it could be about the Z Fighters from Dragon Ball observing the fan - made scenarios in Death Battle fanfiction. Maybe they are reacting to the battles, power - level comparisons, and unique character match - ups that fans create in these fictional stories.
Another great element can be the unique power combinations. For instance, when Broly teams up with other characters, his brute strength combined with Goku's quick thinking or Vegeta's strategic fighting can create really exciting battle scenes.