A male OC could be a bastard son who is shunned by society but is drawn to dragons. He secretly observes dragonlords and learns their ways. Eventually, he tames a wild dragon. His story could involve him using his dragon to seek revenge on those who wronged him in the past, while also trying to find his place in the chaotic world of Westeros.
Another possibility is an OC who discovers an ancient dragon egg in a long - forgotten cave. He manages to hatch it and forms a unique connection with the dragon. This character could then get caught in the middle of the war between the great houses. He might side with a particular house not for power or glory, but because he believes in their cause, and his dragon becomes a crucial asset in the battles.
Another approach is to have the male OC Targaryen be a bastard son. He struggles with his identity throughout the fanfiction. He is initially shunned by both Targaryen loyalists and those who oppose the old regime. However, through his own strength, intelligence, and a bit of luck, he rises in the ranks. He might form an alliance with a powerful house not typically associated with the Targaryens, like the Mormonts. His journey could be about proving himself worthy of the Targaryen name and heritage, all while navigating the complex politics of Westeros.
The male OC Baratheon could also be a bastard son who has been living in exile. He returns to Westeros with a group of loyal followers he has gathered over the years. His main goal could be to claim a small piece of land for himself and his men, but he soon realizes he has to navigate the complex web of politics and allegiances in order to survive.
Perhaps an OC Lannister who is a talented healer. In a world full of wars and battles in Game of Thrones, a healer Lannister could be an interesting addition. They might have to deal with the moral dilemma of healing both their own family's enemies and allies. They could also have a secret love affair with a member of another house, which would add a layer of drama.
A more intense bonding scene could involve the OC having to save the dragon from a trap or danger. As he frees the dragon, there is an immediate sense of gratitude from the dragon. The OC then uses his knowledge of dragon lore (which he could have learned through years of study) to soothe the dragon's wounds. This act of kindness and rescue creates a strong, unbreakable bond between them, and the dragon becomes fiercely loyal to the OC.
The OC can be developed by showing their initial fear and confusion when they first hatch the dragon. For example, they might not know what to do with this powerful and dangerous creature at first. As time goes on, they learn to bond with the dragon, which in turn builds their confidence and sense of purpose.
A fanfiction could center around a dragon rider who is from the Vale. This rider, trained in the Vale's unique fighting style, uses their dragon to patrol the Vale's borders. They become a symbol of hope and strength for the Vale's people. When invaders come, they are met with the fury of the dragon and the skill of its rider from the Vale.
An OC Stark might be more politically astute than the original characters. They could form different alliances, like making a deal with the Iron Bank that gives the North more financial power and influence. This would shift the power dynamics not only in the North but also across Westeros. The original plot of various houses vying for the Iron Throne would be affected as the North becomes a stronger and more independent force.
Perhaps the OC son has a special ability or gift that Jon Arryn was trying to protect him from being exploited for. After Jon Arryn's death, the son has to learn to control this ability while also dealing with the power struggles in King's Landing. He could be a key figure in the fight against the White Walkers, using his unique skills to help the living, all while trying to uphold his father's legacy.
An interesting 'oc game of thrones fanfiction' could focus on an OC who is a female knight in a world dominated by male warriors. She could face discrimination but also prove herself in tournaments and battles. Maybe she becomes a trusted ally of a major character like Jon Snow. Or you could have an OC who is a bard that spreads tales which either inspire or deceive the people of Westeros. Also, an OC who is a foreign diplomat trying to broker peace deals between the warring factions while having their own hidden agenda would be a great concept.
One possible scenario in such a fanfiction could be that the male dragon forms an unexpected bond with an Arryn character. Maybe the Arryn discovers the dragon in a hidden valley and they gradually become allies, with the dragon helping the Arryn in the power struggles within the Seven Kingdoms.