One plotline could be that the OC is a mermaid. Killian Jones, being a sailor, has always been intrigued by the legends of mermaids. When he encounters this OC mermaid, she is in danger from a sea - witch. He decides to help her, and in the process, they form a bond. Their relationship could develop as they explore different underwater and on - land adventures together.
In some fanfictions, Killian Jones might be involved in a time - travel scenario. For example, he could accidentally be sent back to a time before he became Captain Hook. He then has to deal with his former self, trying to avoid changing the future while also coming to terms with who he used to be. It could be a really interesting exploration of his character growth.
There's one where the reader is a time - traveler and accidentally gets stuck in the 'Once Upon a Time' world and meets Killian Jones. They have to work together to find a way for the reader to get back home while falling in love along the way.
One great one to start with could be 'A Pirate's Heart'. It really delves into the relationship between Killian Jones and the reader in a very sweet and adventurous way. It starts with an interesting encounter between the two characters and gradually builds their relationship as the story progresses.
Love and romance are also very common. The OC and Killian usually end up in a romantic relationship. Writers explore different aspects of their love, like the initial attraction, the challenges they face, and how they overcome them. It can range from a slow - burn romance to a more immediate connection.
One popular plotline could be the challenges they face as new parents. Maybe the baby has some special powers inherited from them, and they have to protect the baby from those who might want to use those powers for evil. Another could be a more comical one where Killian is completely clueless about baby - care at first, but Emma finds his attempts endearing.
A common theme is redemption. Since Killian Jones has a complex past, many fanfictions use an OC to be a part of his journey towards redemption. For example, the OC might be the one who believes in him when no one else does.
One great Killian Jones OC fanfiction is 'The Pirate's New Horizon'. It has an interesting original character who gets involved in Killian's adventures in a really engaging way. The story does a wonderful job of exploring Killian's character further through his interactions with the OC.
One great place to start is Archive of Our Own (AO3). There are numerous Killian Jones x OC fanfictions there. You can search for ones with high ratings and lots of kudos. For example, 'The Captain and the Maiden' is a well - written story that delves deep into the relationship between Killian and an original character. It has a rich plot and well - developed characters.
One interesting theme is redemption. Killian Jones, with his complex past, often finds himself on a path of redemption in these fanfictions, especially in relation to his interactions with Peter Pan. For example, in some stories, he tries to make up for his past misdeeds by helping Peter protect Neverland.
One idea could be that Killian is on a quest and stumbles upon a young Emma in a magical forest. He initially mistakes her for someone else but soon realizes her potential. Another could be a time - travel scenario where Killian goes back in time and meets a young Emma, and he has to protect her from a dark force without changing the future too much. And perhaps a story where young Emma is lost in a different realm and Killian is the one who finds her and they form an unlikely bond.