* Exploration of character or story: Fanfiction allows writers to explore characters and stories in a way that the original creators may not have had time or opportunity to do. This can include writing about side characters who didn't get much development in the original story, exploring alternate timelines or events, or even writing sequels or prequels to the original work.
* Shipping: For many fans, shipping (pairing up two characters in a romantic or sexual relationship) is a big part of the fandom experience. Fanfiction can be used as a way to explore these pairings in more detail and create stories that cater to the wishes of the fans.
* Social commentary: Fanfiction can be used as a form of social commentary or to explore topics that the original work didn't address. For example, some fanfiction writers use their stories to explore issues such as race, gender, sexuality, or mental health.
* Artistic expression: For some writers, fanfiction is a form of artistic expression. It allows them to experiment with different writing styles, explore different themes, and create unique and interesting stories.