There's a fanfiction where baby Harley Quinn is raised by a different set of characters. Maybe the Bat - family finds her and tries to raise her in a more positive environment. In this fanfiction, she might grow up with different values compared to her original self, and it could be interesting to see how her personality develops with this new upbringing.
Some fanfictions focus on baby Harley Quinn's relationship with her toys. In this kind of story, her toys could be her only friends at first. She might give them names and have conversations with them as if they were real people. And as the story progresses, she could start to interact with the real world around her in a very innocent and endearing way.
One popular baby Harley Quinn fanfiction could be 'The Adventures of Baby Harley'. It might show a young and innocent version of Harley Quinn getting into cute, non - violent misadventures in Gotham. It could have her befriending other characters in a more child - like way, like a young Joker who is also just a mischievous kid.