One great 'harley and ivy fanfic' to start with could be 'Poison Ivy's Redemption'. It gives a really interesting take on their relationship, showing how they support each other through various challenges.
In a fanfic scenario, perhaps Ivy and Harley are friends and they come across Bruce. They initially have a conflict with him, but then Lemon enters the story. Lemon could be a mediator of sorts. Maybe Lemon has the ability to calm Ivy's plants or Harley's chaotic nature, and helps them to see Bruce in a new light and work together towards a common goal like saving Gotham from a new threat.
The relationship between Harley Quinn and Poison Ivy in the graphic novel is significant as they are often shown as very close friends. They support each other in their various escapades. Ivy's calm and calculating nature often balances Harley's more erratic behavior.
Character development is key. If a 'harley and ivy fanfic' can show how the characters grow and change over time, it becomes popular. Also, an interesting plot. Maybe they go on an epic adventure together or face a new villain in Gotham. It keeps the readers hooked. Another factor could be the writing style. If it's engaging and easy to read, more people will like it.
I highly recommend 'Partners in Crime'. In this fanfic, Harley and Ivy team up to take on some new villains in Gotham. It's full of action and at the same time, shows their relationship evolving. Another one is 'Under the Stars'. It has a more romantic tone as they go on a camping trip together, away from the city lights, and discover new aspects of their relationship while enjoying the beauty of nature.
One common theme is friendship. Their bond is often explored, showing how they support and care for each other. Another theme is redemption. Harley might be seeking redemption from her past actions, and Ivy can play a role in that. And love, of course. Whether it's platonic or romantic, their love for each other is a big part of these fanfics.
First, you need to understand the characters well. Harley is often wild and unpredictable, while Ivy has a strong, protective side. You can start by creating a situation that would lead to their kiss, like a misunderstanding that they need to resolve through their emotions. Keep the dialogue in - character and use their unique voices.
I really like 'Harley and Ivy: Partners in Crime'. In this fanfiction, their personalities are spot - on. Harley's wild and unpredictable nature combined with Poison Ivy's calm and calculating demeanor makes for an exciting read. It also has some really cool plot twists that keep you hooked from start to finish. There's also 'A Tale of Two Outcasts' which delves deep into their backstories and how they came to be friends and partners.