Well, it could be about Naruto being transported to the world where Nightmare Moon exists. Maybe he has to team up with the local ponies to stop Nightmare Moon from causing more chaos. He could use his ninja skills, like his shadow clone jutsu, to outwit her and her minions.
One possible plot is that Nightmare Moon discovers Naruto's chakra and wants to use it for her own purposes. So she captures Naruto. But Naruto, being the determined ninja he is, manages to escape and then decides to take the fight to Nightmare Moon. Along the way, he befriends some of the magical creatures in that world and they help him in his fight against her. He might even learn some new magical abilities during his time there that he combines with his ninja techniques.
Well, it could be about Kotetsu and Izumo facing a really tough mission that turns into a nightmare. Maybe they get trapped in a genjutsu created by a powerful enemy. In this genjutsu, they relive their worst memories, like failing important missions in the past. And they have to find a way to break free together, relying on their friendship and the skills they've developed over time.
I'm not entirely sure as it could be a very unique and perhaps not widely known fanfiction. It might involve Naruto having some sort of connection to a 'nightmare moon' figure, perhaps in an alternate universe where Naruto's origin is intertwined with this strange and probably dark or otherworldly element.
Well, the plot could involve Naruto being mistaken for a new kind of creature in the Nightmare Before Christmas world. The residents there might be curious or even a bit scared at first. Naruto, being Naruto, would try to make friends and show them that he means no harm. He could end up teaming up with Sally to stop some sort of threat to both the Halloween Town and his own ninja world, which he discovers is somehow connected.
Naruto would probably be very friendly and open with the good characters. For example, he would likely be excited to meet Twilight Sparkle and would share his stories of his own world with her. He might be a bit cautious around Nightmare Moon at first, but once he realizes she's a threat, he would be very confrontational.
One idea could be a story where Celestia tries to redeem Nightmare Moon. Maybe she delves into the past to understand what led her sister to turn into Nightmare Moon in the first place and uses that knowledge to slowly break through the darkness. Another plot could be a time - travel fanfic where a character goes back to prevent Nightmare Moon's creation, and has to work with Celestia to do so. Or perhaps a fanfic where Celestia and Nightmare Moon are forced to team up against a greater evil that threatens Equestria.
Well, it could be about Naruto characters somehow getting involved with Gundam technology in a nightmarish scenario. Maybe Naruto and his friends find themselves in a world where Gundam mechas are being used for evil, and they have to fight against it using their ninja skills. It could also involve some sort of dark magic or curse related to the Gundam machines that they need to break.
Another aspect could be the impact of Harry on Nightmare Moon herself. His presence might start to soften her more 'nightmare' - like qualities. As he shows kindness and his own brand of heroism, it could lead to a transformation in Nightmare Moon, and they could end up forming an unlikely but strong bond.
Well, it could be about a Phione trapped in a nightmare world. Maybe it's lost in a dark and distorted version of its own ocean habitat. The plot might involve it trying to find a way out while facing various nightmarish creatures or challenges that are different from the normal Pokémon threats.
A Caius Ballad nightmare fanfic could have a plot where Caius is plunged into a nightmare that blurs the lines between reality and the dream world. He might encounter distorted versions of people he knows, or be in a situation where he is constantly running from an unseen threat. The nightmare could also be a result of a curse or some dark magic, and as he tries to escape, he discovers secrets about himself or his past that he didn't know before. This could lead to a journey of self - discovery within the nightmare, all while trying to break free from it.
Well, there's a fanfic that I really liked called 'Nightmare Moon's New Path'. In this story, she teams up with Twilight Sparkle to face a new threat to Equestria. It's interesting to see how their relationship develops throughout the story. There are also some fanfics that explore her relationship with the other princesses in a more in - depth way.