A common trope is the 'soulmate' concept. In this case, the OC and Rayla are somehow fated to be together, whether it's through a magical connection or just a strong, unspoken bond. The 'rescue' trope is also popular. The OC could be in danger, and Rayla saves them, which then starts their relationship. Or vice versa, Rayla is in trouble and the OC comes to her aid. This creates a sense of heroism and gratitude in their relationship.
There's the 'hidden identity' trope. The OC could be hiding something about themselves from Rayla, like a special power or a secret mission. This adds an element of mystery and suspense to the fanfiction. Also, the 'training' trope can be used. The OC needs to be trained in something that Rayla is good at, like combat or magic. This gives them a reason to spend time together and develop a relationship through the process of teaching and learning.
One popular trope is the 'enemies to lovers' trope. The OC and Rayla could start off on the wrong foot, perhaps having different goals or misunderstandings. But as they are forced to work together, they begin to see the good in each other. Another is the 'fish out of water' trope, where the OC comes from a different background than Rayla, and has to adapt to her world, creating humorous and heartwarming situations along the way.
One popular trope is the 'enemies to lovers' arc. Since they might start off with some differences or even be on opposite sides initially, seeing their relationship develop from that is appealing. Another is the 'hurt/comfort' trope, where one of them gets injured or is in a tough situation and the other helps them out and their bond deepens.
One popular trope is the 'enemies to lovers' kind of story. Since they start off with some differences and mistrust, it's easy to build a story around them growing closer and falling in love. Another is the 'hurt/comfort' trope, where one of them gets injured or is in emotional distress and the other is there to support and heal them.
One popular trope is the 'hidden identity' trope. For example, your OC could be a powerful vampire who has been hiding their true identity from the Mikaelson family for years. Another is the 'love triangle' trope. Your OC might be caught between two main characters, like being in love with Klaus but also having a strong connection with Elijah. The 'fish out of water' trope is also great. If your OC is a new werewolf in the French Quarter, they will be out of their element dealing with the complex politics and power struggles there.
One popular trope could be the 'first time' trope. It might show their initial hesitation and then the passion that builds up as they make out. Another could be the 'interrupted make - out' where something or someone disturbs them at a crucial moment, adding some comical or tense elements to the story.
In Highschool DxD OC fanfiction, the 'Power - Up' trope is quite common. Your OC starts with a certain level of power and then, through training, battles, or special encounters, they gain more power and become stronger. The 'Redemption' trope can also be used. If your OC has made mistakes in the past or has a dark history, they can strive to redeem themselves throughout the story. Also, the 'Chosen One' trope works well. Your OC could be the one chosen to save the supernatural world from a great threat, like an impending war between devils, angels, and fallen angels. This gives them a sense of purpose and importance in the story.
One popular trope is the 'fish - out - of - water' for the OC. For example, if the OC is from a different dimension or has just discovered their powers. They'll be out of their depth in Power Girl's world at first. Another is the 'unlikely alliance' where the OC and Power Girl have to team up despite initial differences. And of course, the 'love interest' trope can also be used, but it has to be done carefully so it doesn't overshadow the main superhero aspects.
In For Honor OC Faction Fanfiction, the 'mentor - student' trope is quite common. An experienced OC could be mentoring a younger, more inexperienced one within the faction. The 'rebel within the faction' trope is also popular. An OC might oppose the traditional ways of the faction and try to bring about change. Also, the 'treasure hunt' trope can be used. The OC faction could be on a quest to find a powerful, ancient artifact that could change their fate.
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 'stranger in a strange land' where the OC is from another world or time and Link has to help them adjust. Another is the 'love at first sight' trope, which is quite common in many fanfictions. And then there's the 'OC with a special power' trope, where the OC has some unique ability that either helps or hinders their relationship with Link.
In Kingdom Hearts OC gamer fanfiction, the 'portal to another world' trope is quite common. Your OC enters the Kingdom Hearts world through some sort of gaming - related portal. This could be a malfunctioning VR headset or a magical game cartridge. The 'team - up' trope is also popular. Your OC teams up with Sora and the gang to fight against the forces of darkness. And the 'lost memory' trope can add an element of mystery. Your OC has lost some of their memories related to their past in the real world or their connection to the Kingdom Hearts world, and they have to regain them throughout the story.