One great 'Joker x Rachel fanfic' could be 'The Unlikely Bond'. It delves into a scenario where Joker and Rachel have a series of unexpected encounters that make them re - evaluate their views of each other. Another could be 'Joker's Redemption through Rachel' which shows how Rachel's goodness might start to change the Joker in some ways. There's also 'Rachel's Dilemma with the Joker' which focuses on Rachel's internal struggle when dealing with the Joker.
You can try Archive of Our Own (AO3). It has a large collection of fanfics from various fandoms, including ones related to the Joker and Rachel. Another option is Fanfiction.net. It has been around for a long time and has a decent amount of 'Joker x Rachel' fanfics.
In Harley Quinn x Joker fanfic, the character development is often a focus. Harley's transformation from a psychiatrist to a criminal sidekick is interesting. Writers may play with different timelines and scenarios in the fanfic. For example, they might explore what would happen if Harley finally broke free from the Joker's influence earlier than in the original story. This can lead to various plot twists and new character arcs for both Harley and the Joker.
One common theme is the exploration of their different worlds. Percy from the demigod world and Rachel from the mortal world. Fanfics often deal with how they bridge this gap.
One common theme is friendship. Many fanfics explore how Ira and Rachel start as friends and how that friendship might develop into something more. Another theme is growth. They both grow as individuals within the relationship, learning from each other. For example, in some fanfics, Ira might learn to be more open because of Rachel, and Rachel might become more confident because of Ira.
The themes in 'joker x harley fanfic' often include the blurred lines between sanity and madness. Both characters are on the edge of sanity, and their relationship is affected by this. Dependency is also a big theme. Harley depends on Joker, and the fics explore how she can become independent. And finally, there's the theme of transformation. Harley might transform from a submissive character to a more assertive one in the relationship.
One popular trope is the 'redemption arc' for the Joker. In some fanfics, there's an attempt to show a softer side of him, perhaps because of Harley's influence. This can be controversial as it goes against the traditional view of the Joker as pure evil.
Writing such sexually explicit fanfic is inappropriate. It violates ethical and moral standards, especially when it involves sexualizing characters from a game or other media. This kind of content can also make many people uncomfortable and goes against the positive and healthy image that the original work may be trying to convey.
One common theme is the battle of ideologies. Bruce Wayne stands for a world of rules and order, while the Joker wants to disrupt it all. Another theme could be redemption, where either character might be on a path to change. Also, the theme of obsession is often present, as the Joker is obsessed with Batman and vice versa.
In 'Bruce Wayne x The Joker Fanfic', their relationship is often complex. It's a clash of two extreme personalities. Bruce Wayne, as Batman, represents order and justice, while the Joker is chaos incarnate. Their interactions can range from intense battles to psychological mind - games. This relationship is what makes many fanfics so interesting as it explores the duality of good and evil in a unique way.