Well, one interesting plot point is often the power clashes. For example, when Naruto's ninja techniques meet Fairy Tail's magic and Irene's dragon - slayer magic. It creates a really cool dynamic of different powers interacting.
The cultural exchange. Naruto characters come from a world of ninja clans and strict hierarchies, while Fairy Tail has a more guild - based, family - like culture. Seeing how they interact and influence each other, for example, a Fairy Tail member learning about the Uchiha clan's history from a Naruto character, is really engaging.
The combination of different powers. Ben's alien powers and Fairy Tail's magic make for some exciting battles.
One interesting plot point is the clash of magic systems. In 'bleach and fairy tail crossover fanfiction', you often see how the spiritual powers from Bleach interact with the magic of Fairy Tail. For example, a shinigami's zanpakuto abilities against a Fairy Tail wizard's elemental magic can create some really intense battle scenes.
One idea could be that Natsu and Irene are forced to team up to defeat a powerful dark magic user. Their opposing personalities at first create conflict, but as they face challenges together, they learn to respect each other's powers.
One idea could be Irene somehow being redeemed through her interactions with Natsu. Maybe she gets a second chance at life and has to learn to be a better person with Natsu as her guide. Another plot could involve Natsu and Irene teaming up against a common, extremely powerful enemy. They start off distrusting each other but gradually come to respect and rely on one another.
Another interesting plot point could be the crossover of the villains. Imagine if some of the powerful dark mages from Fairy Tail team up with the spooky entities that the Ghostbusters usually face. It would create a really challenging situation for both the Fairy Tail mages and the Ghostbusters. Also, there could be a plot where the Fairy Tail guild has to deal with a sudden influx of ghost - like creatures in their world, and they call in the Ghostbusters for help, leading to a lot of cultural and power - based clashes and collaborations.
In some fanfics, the magic from 'Fairy Tail' is introduced to the world of 'RWBY'. This can lead to really cool battles where the RWBY characters have to adapt to new types of powers. For example, Ruby might encounter a Fairy Tail mage who can control fire, and she has to figure out how to fight against that new threat.
The unique character of Irene in Fairy Tail. Her backstory and complex personality can be explored in interesting ways in lemon fanfiction. It adds a new dimension of adult - like relationships and emotions to her character.
Perhaps a plot where the Anbu and Fairy Tail characters swap abilities or powers for a time. The Anbu would have to use Fairy Tail magic in the Naruto world, and the Fairy Tail mages would have to rely on ninja skills. This would lead to some really unique and humorous situations. Also, a story about a hidden connection between the Anbu organization in Naruto and a secret group in Fairy Tail. They discover that they have a common origin or purpose that has been long forgotten, and they must work together to uncover the truth and face the threats that come with this discovery.
A great plot twist would be if the Fairy Tail guild members were transported to the Naruto world and had to adapt to ninja life. Or perhaps a character from Naruto, like Sasuke, gets corrupted by the dark magic in the Fairy Tail world. It would create a whole new dynamic as the other characters try to save him. Also, what if there was a prophecy in both worlds that the only way to save them was for a Fairy Tail wizard and a Naruto ninja to sacrifice themselves? That would be a very intense plot twist.