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.
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.
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.
In some fanfiction, a really interesting storyline is when Harley and Ivy get separated for a while. It shows how much they rely on each other. Harley starts to lose her spark without Ivy around, and Ivy feels a bit lost without Harley's energy. When they finally reunite, it's a very emotional moment, and they realize how important their friendship is in the chaotic world of Gotham.
Well, in Poison Ivy and Harley Quinn fanfiction, a common theme is their loyalty to one another. They are like two peas in a pod. Ivy's connection to nature can sometimes be used to protect Harley. For example, she might use her plants to create a hiding place when they're on the run from the police or other bad guys. And Harley, in turn, is always there to cheer up Ivy when she's feeling down about her failed attempts at environmental conservation in Gotham.
Character development is key. Harley's journey from being Joker's sidekick to finding her own identity with Ivy by her side. And Ivy's growth as a character, her connection to nature and how that affects her relationship with Harley. Also, a unique plot. Maybe something like they go on a quest to save a part of Gotham's nature that's being destroyed, which ties in with Ivy's character. It should also have good dialogue that reflects their personalities, like Harley's crazy but endearing one - liners and Ivy's more serious, nature - centric statements.
One possible fanfiction could be about Batman trying to reform Poison Ivy and Harley Quinn. Maybe he sees potential in them to turn away from their criminal ways. He could start by trying to understand their motives better, like Ivy's love for plants which has led her to extreme actions to protect them, and Harley's loyalty to Ivy which has made her follow along in the chaos.
One great 'Harley Quinn x Poison Ivy Fanfic' is 'Green and Red'. It really delves into their complex relationship, showing how they support each other through different challenges in Gotham. The way it describes their interactions is both true to their characters and also adds a new layer of depth to their bond.