One idea could be to explore what if Gohan had a different training partner before the Cell Games. For example, if Piccolo had trained with him more intensively, it might have changed his power level and fighting style during the games.
One possible fanfic could be about Goku's intense training before the Cell Games. He might be shown pushing his limits in the Hyperbolic Time Chamber, trying out new techniques and forms to defeat Cell. Maybe he discovers a new power level that no one, including himself, expected.
First, think about the characters you want to focus on. Are you more interested in Goku, Gohan, or the other Z - fighters? Once you've decided, consider their personalities and how they would react in different situations during the Cell Games.
One interesting aspect could be the different character interpretations. In fanfiction based on DBZ Cell Games footage, authors might explore new sides of Goku, like his internal thoughts during the intense battles. For example, they could delve into how he really felt facing Cell's powerful forms.
By having unique plot twists. If the fanfiction has a plot that no one has thought of before, like a time - traveling element where a future version of a character comes back to change the outcome of the Cell Games, it will attract more readers.
The theme of transformation is also popular. It could be a physical transformation of the female Cell, or a more emotional and mental one as she navigates the complex world of DBZ, often changing from a more villainous or neutral stance to a more heroic one.
One interesting fanfiction could be where Cell somehow ends up in the Naruto universe. Maybe he's a new type of enemy that the ninja have to face. It could bring a whole new level of danger as his powers are different from the normal jutsu - based attacks in Naruto.
If Goku and Female Cell interacted, it could change the perception of enemies in the DBZ universe. Their cooperation might lead other fighters to be more open to the idea of redeeming former foes. For example, if they manage to work together successfully, Vegeta might rethink his stance on some of the villains he's faced.
A great plot point could be Goku teaming up with an unexpected ally during the Cell Games. For example, an old enemy who realizes that Cell is a greater threat. They could combine their powers in a unique way to take on Cell.
Maybe in the fanfiction, Cell could be re - created in a different form with a mix of other characters' DNA. He could have some of Piccolo's regeneration abilities along with Gohan's hidden power. This would lead to a whole new set of battles and power - level dynamics as the Z - fighters try to figure out how to deal with this new Cell.