A possible plot is that an alien race tries to capture Godzilla's harem. Godzilla has to fight not only the alien invaders but also deal with the fear and worry of his harem being in danger. The harem members might also try to use their wits and any hidden abilities they have to escape or assist Godzilla in the fight.
One interesting plot could be Godzilla protecting his harem from other kaiju threats. He uses his powerful atomic breath and strength to keep his mates safe.
In some fanfiction, there could be a scenario where a human with special powers is the only one who can stop Female Godzilla from going on a rampage. But as they interact, they start to understand each other's motives, and the human realizes that Female Godzilla is acting out of self - defense due to the harm humans have caused to her habitat.
In a fanfiction, there could be a story where a pony discovers a magical artifact that can control Godzilla. At first, the pony uses it for fun, making Godzilla do small things like create waterfalls with its tail. But then, an evil force tries to steal the artifact to use Godzilla for destruction. The ponies then have to protect the artifact and convince Godzilla to help them fight the evil.
One common plot is the friendship between Baby Godzilla and Mothra. For example, they might team up to face a new threat in their world, using their unique abilities to overcome challenges.
One possible interesting plot could be a unique alliance between Godzilla and Mothra against a new, more powerful enemy. Maybe this new foe has the ability to disrupt their natural powers and they have to find a way to combine their strengths in a different way than before.
Well, a plot might be that Dark Naruto in the fanfiction is on a journey to change the ninja world with his harem by his side. They could be facing off against the established shinobi villages' old ways. For example, they might try to create a new system where power is more equally distributed among all ninjas, not just the elite families. And the harem members could each have special skills that contribute to this goal.
Well, sometimes in these fanfictions, there's a plot where Naruto has to protect Hanabi and the other members of the harem. Maybe there's a new threat to the village and Naruto's harem becomes a sort of team. Hanabi might be the one who initially challenges Naruto's leadership in this group but then gradually comes to respect and support him. And along the way, there are the typical romantic sub - plots as Naruto tries to balance his relationships with everyone in the harem.
A really interesting plot could be that Naruto, as a god, has to train the members of his harem to become stronger. This could involve him teaching them unique ninja techniques, and during this process, romantic relationships develop and there are also character growth arcs for the harem members.
Well, perhaps a plot where the harem members in the 'evil naruto harem fanfiction' have to deal with the consequences of being associated with an evil Naruto. They might face opposition from the regular Naruto's friends and have to fight to protect their relationship with him. It could also involve the harem members trying to change Naruto from his evil ways, leading to some really emotional and tense moments.
One interesting plot could be the discovery of the dragon egg in a hidden, enchanted place. The protagonist, who is in a harem setting, then has to protect the egg from various villains who want to use its power for evil. This often leads to exciting battles and the formation of new alliances within the harem.
One interesting plot could be Harry and Katie going on magical adventures together in a world full of unique creatures. Another could be them facing a powerful dark wizard and having to use their combined skills to defeat it. Also, perhaps a plot where they discover a hidden magical realm and have to figure out how to navigate it while also dealing with their growing relationship within the harem dynamic.