Often, the clash of different powers and abilities is really interesting. For example, the superpowers of Young Justice characters against the magic of My Little Pony ponies.
The cultural exchange between the two universes can be a great plot point. Like how the heroes from Young Justice might view the peaceful society of Equestria, and how the ponies would react to the more complex and sometimes violent world of Young Justice. There could be ponies trying to introduce their ways of friendship and harmony to the Young Justice team, while the team might be trying to show the ponies how to defend against more serious threats. It makes for a really engaging story as they learn from each other.
The idea of a common enemy that forces the characters from both universes to work together is also very appealing. This enemy could be something that neither world has faced before, and they have to combine their unique skills and resources. For instance, a powerful dark magic being that is immune to the Young Justice's physical attacks but can be countered by the magic of the ponies, and vice versa. So, they must figure out a way to cooperate and defeat it.
One popular 'Young Justice My Little Pony crossover fanfic' is 'Equine Justice'. It combines the action - packed world of Young Justice with the colorful and magical world of My Little Pony in an interesting way.
One interesting plot point is the power dynamic. Naruto is extremely powerful in his own right, with his chakra and jutsu. When he enters the Young Justice world, it shakes up the existing power structure. For example, in some fics, his Rasengan is a completely new and unheard - of power for the Young Justice characters, and they have to figure out how to work with it. Another plot point is the clash of cultures. Naruto comes from a world of ninjas, with strict codes and traditions. In Young Justice, it's a different set of ethics and values. How they interact and influence each other is really engaging.
One interesting plot point is the clash of values. My Little Pony is all about friendship and harmony, while Star Wars has the battle between good and evil in a more complex galactic setting. So when the ponies enter the Star Wars universe, how they try to spread their message of friendship among the war - torn factions can be really engaging.
Well, in my opinion, the friendship between the ponies is the most interesting plot. They come from different backgrounds and have different personalities, yet they always support each other. For example, Twilight Sparkle is a bookish pony, and Pinkie Pie is always full of energy. Their interactions and how they grow together in friendship is really engaging.
One idea could be that the Young Justice team has to prove themselves to the Justice League during a major alien invasion. The League initially doubts their abilities but as the battle progresses, they see the unique skills and teamwork of the young heroes.
In Young Justice vs Avengers fanfiction, a great plot point is the generational gap. The Avengers are more established and have a history, while Young Justice is the new generation trying to prove themselves. This can lead to interesting dynamics like the Avengers initially underestimating Young Justice, only to be proven wrong. Additionally, the different ethical stances of the teams. Young Justice may be more willing to take risks and bend the rules a bit, while the Avengers often uphold a more traditional view of justice. And of course, the potential romances that could develop between members of the two teams add a whole new layer of intrigue.
One common theme is friendship. Just like in My Little Pony, the Young Justice characters often form new friendships or strengthen existing ones when they interact with the ponies. Another theme is the clash of different worlds and cultures. Since they come from different universes, there are always interesting situations when their values and ways of life meet.
I think Luna from My Little Pony and Severus Snape would be quite interesting. Luna has her own struggles with her past and redemption, much like Snape. Their brooding natures could lead to some very deep and complex conversations, perhaps about forgiveness and second chances.
One possible plot could be that the ponies accidentally enter the wizarding world. They might be mistaken for strange magical creatures at first. Twilight Sparkle could be fascinated by the complex magic in Harry Potter's world and try to learn some spells, while Harry and his friends are intrigued by the ponies' unique magic of friendship.
One possible plot could be that Godzilla somehow gets transported to the world of My Little Pony. The ponies are initially terrified, but then they realize Godzilla is there because he's being chased by an even greater threat from his own world. So, the ponies, with their magic, decide to help Godzilla fight off this threat and in the process, they learn about each other's strengths and form an unlikely friendship.