Often, they highlight their shared love for food. Since they are both in the culinary world in the original story, fanfics usually revolve around cooking challenges they face together or how they teach each other new techniques.
There's 'Yuji and Nobara: Unseen Connections'. This fanfic delves deep into their friendship that could potentially turn into something more. It has some really interesting scenarios where they rely on each other's strengths and learn from their weaknesses.
One common theme is the discovery of love. Takumi and Megumi often start as friends or acquaintances and gradually realize they have deeper feelings for each other. Another theme could be personal growth. Through their relationship, they both learn more about themselves and become better individuals.
Love and friendship are also big themes. It can start as a friendship that slowly blossoms into love. The journey of how their relationship evolves from just acquaintances to something deeper is often explored. Like in some fanfics, they start as classmates at Jujutsu High and then feelings start to develop over time.