Interesting character development within the fanfic is key. Maybe Hayama Hayato starts to see things from Hikigaya Hachiman's perspective more, or vice versa. Their growth as characters, learning from each other, and how that affects their relationship with other characters in the fanfic world can make it a great read. Also, if the fanfic is set in a unique AU (Alternate Universe), like a fantasy or a historical setting, it can add a whole new layer of intrigue.
You can start by looking on fanfiction platforms like Archive of Our Own (AO3). There are often many works dedicated to different character pairings. Just use the search function and type in 'Hayama Hayato x Hikigaya Hachiman'. Another option could be FanFiction.net, although the content there may vary in quality. Some anime - related forums might also have threads where fans recommend good fanfics about these two characters.
One great Hayato x Ryuuichi fanfiction could be 'The Bond Beyond Words'. It beautifully depicts their relationship development, starting from their first encounter and gradually showing how they understand and support each other. The story is filled with emotional moments that really bring out the connection between the two characters.
One common theme could be friendship development. Maybe the stories show how Hayato and Ryuuichi start as acquaintances and gradually become closer friends. Another theme might be adventure, where they embark on some sort of journey together.
One common theme is acceptance. They come from different backgrounds and have different personalities, so accepting each other for who they are is important. Also, the theme of loyalty often shows up. They support each other through various situations in the fanfics.
Good 'hachiman x yui fanfic' often has in - depth characterizations. Since Hachiman is a complex character with his cynical views and Yui is more outgoing, getting their personalities right is crucial.
Another theme is the exploration of their personalities. Since both Hachiman and Yukino have complex personalities, fanfictions may focus on how these personalities interact and complement each other. It could be about how Hachiman's cynical view and Yukino's cold exterior start to break down in each other's presence.
One of the main themes could be the contrast between their personalities. Hachiman's cynical nature and Totsuka's more positive and friendly nature can create interesting dynamics. This contrast can lead to themes like acceptance, where they learn to accept each other's flaws and differences. Additionally, themes related to the world they inhabit, such as school life and social interactions, can be incorporated into the fanfics as a backdrop to their relationship.
I'm not sure specifically which 'hachiman x totsuka fanfic' is the best. You could try searching on some popular fanfic platforms like Archive of Our Own. There might be a variety of works there that could satisfy your interest.
There are some dedicated anime or manga fanfiction communities as well. For example, Reddit has certain sub -reddits where fans share and discuss fanfictions. You could post a request there asking for Hayato x Ryuuichi lemon fanfiction. Additionally, Tumblr sometimes has bloggers who post or reblog fanfictions, so it's worth a look.