There are several common tropes. The 'mysterious heritage' trope is often used. The human OC has a mysterious past or heritage that is slowly uncovered throughout the fanfic. The 'fish - out - of - water' trope is also present. They are a human in a world full of Soul Reapers and Hollows, so they feel out of place at first. And the 'redemption arc' trope can be found, where the OC may have made some mistakes in the past and is now on a path to redeem themselves in the Bleach universe.
In Bleach human OC fanfics, a popular trope is the 'orphan with a great destiny' trope. The OC is usually an orphan who then discovers they have a special role to play in the world of Soul Reapers and Hollows. The 'training montage' trope is also common. The OC trains hard to improve their powers and skills, often with the help of a more experienced character. Additionally, the 'rivalry with a canon character' trope can be seen, where the OC has a friendly or not - so - friendly rivalry with someone like Renji or Byakuya.
One common trope is the 'hidden power' trope. The human OC often has some latent power that they don't know about until a crucial moment. Another is the 'outsider who becomes a hero' trope. They start as an ordinary human in the Bleach world but gradually rise to become important. And there's also the 'love interest of a main character' trope, where the OC ends up in a romantic relationship with someone like Ichigo or Rukia.
One common trope is the 'gamer - in - a - strange - world' concept. The OC, being a gamer, finds themselves in the Bleach universe and has to adapt. Another is the 'level - up' trope. Just like in games, the OC gains power and abilities as they progress through the story. For example, they might start as a weak character and gradually become a powerful Soul Reaper or Arrancar. The 'unique - ability - from - gaming' trope is also popular. This is where the OC has an ability that is related to their gaming skills, like being able to analyze an opponent's moves like it's a game strategy.
One popular trope is the 'powerful outsider' where the OC has some extraordinary power that the main characters in Supernatural don't have, like the ability to control the elements. Another is the 'lost love' trope, where the OC has a past relationship with one of the main characters that ended traumatically. And the 'mysterious origin' trope is also common, where the OC's true nature or where they came from is a big mystery throughout the fanfic.
Some great tropes for Bleach female OC fanfiction are the 'chosen one' trope. Your character could be chosen by some ancient power to save the Soul Society. The 'fish out of water' trope is also good. If your OC is from a different dimension or realm, she'll have to adjust to the Bleach universe. And then there's the 'redemption arc' trope. Maybe she was once a bad guy but is now trying to make amends. These tropes can add depth and familiarity to your story.
One popular trope is the 'newcomer' OC. For example, an OC who is a new vampire or werewolf in the Being Human universe. They often struggle to adapt to the rules and society of these supernatural beings. Another is the 'love interest' OC. This could be an OC who falls in love with one of the main characters, like Aidan or Sally, adding a new layer of romantic drama to the story.
One common trope is the OC being a new student or outsider in the fanfiction world. For example, in a Harry Potter fanfic, an OC might be a transfer student to Hogwarts. Another is the OC having a special power or ability that sets them apart. They could be the only one who can communicate with a certain magical creature. Also, the OC might become a love interest for a canon character, like an OC falling in love with Sherlock Holmes in a Sherlock fanfiction.
Some common tropes in villain oc fanfiction include the 'seductive villain' trope. This is when the villain uses their charm or attractiveness to manipulate others. It can add an interesting dynamic to the story. The 'vengeful villain' trope is also quite common. They are seeking revenge for some past wrong done to them. And then there's the 'evil legacy' trope. The villain oc is following in the footsteps of an even greater evil from the past, and they are trying to live up to that reputation or complete some unfinished evil business.
Well, 'Hidden Potential' is a big trope. A Senju character in fanfics may seem ordinary at first but then discovers they have some amazing hidden potential within them related to their Senju heritage. 'Senju and the Tailed Beasts' is also common. Fanfics might explore how a Senju could potentially bond with or control a tailed beast in a way different from what we've seen in the original Naruto story. There's also the 'Ancient Prophecy' trope, where a Senju is part of an ancient prophecy that dictates their actions and the future of the Naruto world.
Alternate universe scenarios are also very popular. This could be where the characters have different abilities or the story takes place in a completely different setting, like a modern - day version of the 'bleach' world. Another theme is character relationships. Fans often like to explore the friendships, rivalries, or romances between characters in more depth than the original work allowed.
One common trope is the 'demon protector'. The demon takes on the role of guarding the reader from other threats in the story, whether they be other demons or some sort of dark magic. Another is the 'forbidden love' trope, as in the demon and the reader come from different worlds (human and demon) and their relationship is frowned upon by society in the fic's setting. And there's also the 'demon with a heart of gold' trope, where the demon may seem menacing at first but is actually kind - hearted deep down especially when it comes to the reader.
One common trope is the 'forbidden love' between the OC and Dracula. The OC, whether human or vampire, finds themselves drawn to Dracula's dark allure despite the danger. Another is the 'newbie in the vampire world' trope, where the OC is a newly turned vampire trying to navigate the rules and power dynamics in Dracula's domain.