One common theme is secrecy. Since they are black ops, the stories often revolve around classified missions and information that must not be leaked. For example, in many fanfictions, the characters have to keep their identities and missions hidden from their friends and family in the village.
The story of Black Ops 3 is somewhat related to Black Ops 2. Some storylines and events carry over or have references that link the two. But it's not a direct continuation; there are new elements and developments too.
The story of Black Ops 4 is separate from Black Ops 3. They have different settings, characters, and plotlines. Although they belong to the same franchise, the narratives are independent of each other.
Sakura could be one of his teammates. She has her medical ninjutsu skills which would be useful in treating injuries during missions. Also, her super strength could come in handy in combat situations.
The mystery factor. In the Naruto world, the black ops are always shrouded in secrecy. Fanfics about them allow us to peek into that mystery. For example, we get to see their special training methods and unique jutsus.
One interesting Naruto Anbu Black Ops fanfiction could be one where a new character is introduced into the Anbu and has to deal with the secrecy and danger. For example, a story where this new Anbu member discovers a hidden plot within the organization itself.
Well, it could be about Naruto using his ninja skills in special ops missions. Maybe he's part of a team that has to infiltrate enemy bases. He'd use his shadow clone jutsu to create diversions and his rasengan to take out tough opponents.
One popular 'naruto black ops fanfic' is 'The Black Ops Chronicles'. It delves into the secret missions and the hidden aspects of the Naruto world that the regular series doesn't fully explore. The characters are well - developed, and the plot is full of twists and turns.
The main characters could be some of the lesser - known but powerful shinobi from the Hidden Leaf. For example, Might Guy. His unwavering determination and powerful taijutsu could be a great asset. Then there's Ino. She could use her mind - transfer jutsu to gather information from the zombies or the source of the zombie outbreak. And Neji, with his Byakugan, could see the weak points of the zombies and direct the attacks of the Black Ops more effectively.
Kakashi is often a popular character in Naruto Anbu Black Ops fanfiction. His cool and mysterious nature during his Anbu days makes him an interesting subject. Writers like to explore his past missions and his relationships with other Anbu members.