One idea could be that Riki and Kurugaya go on a secret adventure outside of the usual Little Busters' activities. They discover an old, forgotten place in town that holds a special meaning for Kurugaya's past.
A cool idea could be a time - travel fanfic. Riki and Rin find themselves sent back in time to when the Little Busters first formed. They have to deal with the knowledge they already have while trying not to disrupt the past too much.
In some fanfictions, a plot twist could be that Riki loses his memory related to Rin. This creates a lot of angst and confusion. Rin has to work hard to make Riki remember their relationship, and during this process, they both grow and change in unexpected ways.
In many Little Busters fanfictions, Rin and Riki often have a very special relationship. Riki usually plays a role of support for Rin. He tries to understand her complex personality. For example, Rin's shy and sometimes wild nature is something Riki has to navigate through. Their relationship can be seen as a deep friendship with potential romantic undertones. Riki's patience and Rin's gradually opening up to him make their interactions in fanfictions really interesting.
The emotional depth in these fanfictions can be really engaging. Since Riki has his own insecurities and Rin has her own issues, fanfic authors can really dig deep into how they help each other grow. Some fanfics show Riki becoming more confident because of Rin's straightforwardness, and Rin learning to be more open because of Riki's gentle nature.
By showing small, everyday interactions. For example, Riki sharing his lunch with Kurugaya when she forgets hers. These simple acts can gradually build a connection between them.
One idea could be a little one in a magical world where they discover they have special powers. For example, they can communicate with animals and go on adventures with their new furry friends to save the enchanted forest from an evil sorcerer.
One idea could be exploring the vampire's family history more in - depth. Maybe there are ancient secrets or rivalries within the vampire clan that the main characters could uncover.
The little bat could discover a hidden cave filled with ancient bat artifacts. It then has to protect this cave from other animals who might want to take over or destroy it. This could involve making alliances with other bats and using its wits to outsmart the invaders.
One idea could be exploring what would happen if Ariel had a secret power she didn't know about until after she became human. For example, she could have the ability to communicate with all sea creatures, not just the ones she already knew. This would create new challenges and relationships on land.
One idea could be that the little merman discovers a hidden underwater kingdom full of magic and mystery. He could be on a quest to find a powerful artifact that can save his own kingdom from a dark force. Another plot could be a love story where he falls in love with a human who can also breathe underwater due to a special spell.