Well, a plot could revolve around Villain Deku trying to recruit Uraraka to his side. He might start by showing her the flaws in the hero society that she's a part of. Uraraka, initially resistant, starts to question her own beliefs as Deku keeps presenting her with evidence of the corruption and inequality. This could lead to a very complex relationship between them, where she's torn between her loyalty to the heroes and the allure of what Deku is offering. Or perhaps there's a parallel universe where Deku was always a villain and Uraraka is the only one who can reach the part of him that was once good.
For Villain Deku, his character can be developed by showing his descent into villainy. Maybe he starts off with small acts of rebellion against the hero system that he once idolized, gradually becoming more extreme. His relationship with Uraraka can be a catalyst for this change, either pushing him further into the dark side or causing him to question his actions. For Uraraka, she can develop by having to face a friend - turned - enemy. This forces her to grow stronger, not just in terms of her quirk, but also emotionally as she has to deal with the betrayal.
As of the latest chapters, Izuku and Uraraka have shown some mutual interest and closeness, but it's not a definite romantic pairing yet. It's still evolving in the story.
I'd recommend 'Uraraka's Secret Admirer'. In this fanfic, the reader is Uraraka's secret admirer and there are a lot of sweet and shy moments between them. It's well - written and the characters' emotions are portrayed vividly.