One common theme is friendship. The original characters often form strong bonds with Fitz, like in many fanfictions where they start as colleagues and end up as close friends.
One common theme is the exploration of Fitz's intelligence. The fanfictions often show how the reader is attracted to his brilliant mind. Another theme is the idea of trust, as Fitz has had issues with trust in the original story, and in the fanfictions, it's often about building trust between him and the reader.
One common theme is forbidden love. Since Leo is a Whitelighter and has certain rules, an OC often challenges those boundaries, leading to a love story filled with obstacles. For example, they might have to hide their relationship from the Elders.
There's 'Fitz's Unlikely Ally' which is an interesting leo fitz oc fanfiction. In this story, the original character has a unique ability that helps Fitz in a dangerous mission. The story is full of action and also some great character development for both Fitz and the OC.
One common theme is forbidden love. Their relationship often has many obstacles in the stories, just like in the original context where they face many challenges due to their different positions and circumstances.
Love and support. Their marriage is often depicted as a partnership where they support each other through various challenges in the Lost Cities. For example, in many fanfictions, when one of them faces a difficult political situation, the other is right there to offer advice and a helping hand.
A common theme is their scientific adventures together. Since they are both scientists, many fanfics focus on them solving complex problems in the lab or in the field.
One common theme could be the challenges they face as new parents. Since their relationship has always been complex, adding a baby into the mix would surely bring a whole new set of problems to deal with.
Friendship is a common theme. Writers might explore how their friendship could develop in different scenarios, like facing a big challenge together.
One common theme is romance. It often focuses on the relationship between Ezra and the reader, with lots of sweet moments, like first dates or declarations of love.
One common theme could be emotional hurt. Leo might be betrayed by a friend or a loved one, which causes him great emotional pain. This could lead to him becoming withdrawn or having trust issues.