One common theme is the exploration of their relationship in different universes. For example, in some fanfics, they might be in a world where Gotham is more peaceful, and they can focus more on their personal relationship without the constant threat of villains.
Sure, Rachel Dawes is part of the Batman comic world. Her presence adds depth and complexity to the overall narrative of Batman's adventures in Gotham.
Another option is to follow Batman fanfic communities on social media platforms like Tumblr or Twitter. Fans often share their works or recommend others' works there. You can search for relevant hashtags such as #BatmanRachelFanfic.
You can start by looking on popular fanfiction websites like Archive of Our Own (AO3). It has a large collection of fan - created works, and you're likely to find several 'Batman and Rachel' fanfictions there. Just use the search function and type in 'Batman and Rachel' and you'll get a list of relevant stories.
There might be a fanfiction where Batman has to save Rachel from a new super - villain in Gotham. This could explore their relationship deeper as Batman realizes how much Rachel means to him while fighting to keep her safe. Maybe in this story, Rachel also plays a key role in helping Batman understand the villain's motives better.