One common theme is self - discovery. Menma often finds himself in new and strange worlds in these crossovers, and he has to figure out who he is and what his place is. For example, when he crosses into a different anime world, he might start questioning his own ninja values.
One popular 'menma uzumaki crossover fanfiction' is 'Menma in the World of Naruto Shippuden Crossovers'. It's really interesting as it shows Menma interacting with different characters from the Naruto universe in unique ways.
Sakura could be really interesting. She might be confused at first by Menma's presence, thinking he's some kind of impostor Naruto. But as she gets to know him, she could see his unique qualities and might even develop a friendly rivalry with him. Another interesting character could be Kakashi. He would be observing Naruto and Menma's interactions closely, maybe even giving them some special training to help them work together better.
Naruto could be a great character to pair with Menma. Their personalities could create an interesting dynamic. Naruto's determination and Menma's more gentle nature could complement each other well in a story about friendship or even a budding romance.
In many of these fanfictions, Naruto is the main protagonist we all know from the anime and manga. He brings his determination and his never - give - up attitude. Naruko, as an interesting addition, might add a different dynamic, maybe with a different approach to her ninja skills or relationships. Menma, on the other hand, can be the wildcard. He might have a mysterious past or a special power that sets him apart, and his actions and decisions often drive the plot forward as much as Naruto's or Naruko's do.
I'm not sure who the absolute best is, but some authors who are quite popular in the Naruto Menma fanfiction community are those who really capture Menma's character well. For example, some authors focus on his internal struggles and how he deals with being in Naruto's shadow in a way that feels very real.
In Naruto Menma Chronicles fanfiction, Sakura can be a main character too. She might be involved in helping Menma with his medical needs or in battles, using her skills as a ninja. Another important character could be Sasuke. He might be a rival or an ally to Menma, depending on the direction of the fanfiction. His power and his complex personality add a lot to the story.
In these fanfictions, Naruto's character is often based on his canonical self, which is full of energy and a bit of a goofball at times. Menma, on the other hand, may be a bit more mysterious or have a different backstory that shapes his character. But they can both have a strong sense of justice. Naruto has always fought for what he believes is right in the main series, and Menma can be written to have a similar moral compass in fanfiction. They may also both experience growth throughout the story, learning from their mistakes and becoming better ninja.