Love triangles are quite common. There could be a love triangle between Batman, Harley Quinn, and Poison Ivy. Sometimes Harley might be caught between her old feelings for the Joker and new feelings for Batman or someone else. The theme of female empowerment is also prevalent. Fanfics often showcase Poison Ivy's strong connection to nature and her ability to use it as a force, and Harley Quinn's growth from a sidekick - like figure to a more independent character.
Friendship is another big theme. Despite their different personalities, they form a bond. In some fanfics, they start out as rivals but gradually become friends. Their friendship is shown as something that makes them stronger. For instance, they might help each other out of tough situations like escaping from Arkham Asylum.
A common theme is friendship. Their unique bond, whether it's a platonic or a more romantic - leaning one, is often explored. It shows how they support each other through Gotham's chaos.
In a fanfiction where Poison Ivy and Harley Quinn are married, their life could be full of adventure. They might use their combined skills to take over Gotham's underworld in a more 'eco - friendly' way. Ivy could use her plant powers to create barriers and traps, while Harley with her acrobatic skills and unpredictable nature could be the distraction. Their relationship would be a blend of passion and chaos, constantly keeping each other on their toes.
A possible plot for a Poison Ivy and Harley Quinn fanfic could be that they are framed for a crime they didn't commit. They then have to go on the run from the law and Batman. As they are running, they discover a secret underground garden that has plants with magical properties. Ivy wants to study these plants, but they also have to be careful not to be caught. Meanwhile, Harley is constantly cracking jokes and getting them into even more trouble, but also helping them out in unexpected ways.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). There are often a great number of fanfics related to Batman, Harley Quinn and Poison Ivy there. The search function allows you to filter by various criteria such as rating, length, and genre. Another option is FanFiction.net, which has been a long - standing platform for fan - created stories. Some Tumblr blogs also curate and share interesting fanfics in this fandom.
One key moment is when they support each other through their various escapades in Gotham. Another is when they stand up against common enemies together, which deepens their bond.