One common theme is friendship. Since Sero is part of a hero class, many fanfictions explore his friendships with his classmates like Midoriya and Bakugo. Another theme is his quirk development. Writers often focus on how Sero can improve his tape quirk.
There's a fanfiction called 'Sero's Adventure'. In this story, Sero embarks on a solo adventure where he discovers a new aspect of his quirk. It's really interesting as it delves deep into his character. Also, 'Sero in the Spotlight' is a good one. It puts Sero in the center of a major event, showing his growth and leadership skills.
One great Todoroki and Yaoyorozu fanfiction is 'A New Bond'. It focuses on their teamwork during a difficult mission at school. The story beautifully portrays how their different quirks complement each other.
The character's personality traits being highlighted in an endearing way can make a Todoroki fanfic cute. For instance, Todoroki's initial shyness or his confusion about normal, everyday things can be really charming. If the fanfic shows him blushing when complimented or his awkward attempts at small talk, it adds to the cuteness factor.
Once upon a time, there was a Todoroki sister OC named Hana. She had the same white and red hair as her brother Shoto. Hana was often in the shadow of her powerful siblings. But she had a unique power of her own - the ability to manipulate ice and fire separately, not just together like Shoto. One day, she decided to prove herself. She entered a hero competition at school. At first, everyone underestimated her. But as the challenges went on, she showed her true strength, impressing everyone with her precise control over her powers.