Power struggles are quite common too. Each member of the team has their own set of abilities and sometimes there can be a bit of a power struggle as they try to figure out who is in charge or who has the most useful skills in a particular situation. It adds an interesting dynamic to the fanfiction stories.
One common theme is the corruption of innocence. Sonic, who is typically seen as a pure and heroic character, is corrupted in these fanfictions. Another theme is the struggle between good and evil within himself. Also, the idea of power corrupting is often explored, like Sonic getting too much power and it leading him to the dark side.
One common theme is redemption. Sally might try to redeem Dark Sonic. Another theme could be the power of friendship, showing how their relationship overcomes the dark side of Sonic. Also, adventure themes are common, with them going on quests together.
In a Team Sonic vs Team Dark fanfiction, a great storyline could be that an ancient prophecy predicts that one of the two teams will bring either great peace or great destruction. This causes a huge rift between them as they both believe they are the ones meant to bring peace. There could be epic battles as they try to prove their worth. Or perhaps there's a parallel universe where the roles of the teams are reversed. Team Sonic is the more brooding and serious group, while Team Dark is the more heroic and light - hearted. The two teams from different universes meet and have to figure out how to coexist.
One common theme is redemption. Dark Sonic is often seen as a character in need of redemption, and Amy can be the catalyst for that change. Another theme is the power of love, showing how Amy's love for Dark Sonic can transform him. Also, there's the theme of good vs. evil, with Dark Sonic representing the 'evil' side and Amy the 'good', and their relationship blurring the lines between the two.
There could be new original antagonists created specifically for the fanfiction. These might be dark entities that are related to the source of Dark Sonic's power, trying to either control him or use his power to spread chaos in Sonic's world.
It's really hard to say. Team Sonic has Sonic's incredible speed and agility, along with Tails' intelligence and Knuckles' strength. But Team Dark has Shadow, who is also extremely powerful and fast, plus Rouge's skills and Omega's firepower. In a fanfiction, it could go either way depending on how the author wants to write it. Maybe Sonic's team wins because of their strong bond and teamwork, or perhaps Team Dark's more edgy and unpredictable nature gives them the edge.
One common theme is redemption. Dark Sonic is often a character in need of redemption, and Amy can be the catalyst for that. Another is the power of love or friendship, as Amy's connection to Dark Sonic might start to change him.
One common theme is friendship. Sonic and Sonic (even if they are different versions) often form a unique bond, and their friendship with Amy is explored in different ways. It could be about how they support each other through tough times.
One common theme is friendship. Sonic and his friends' relationships are often explored in depth, like how they support each other during tough times. Another theme is adventure. They go on various quests, whether it's to save the world or find a hidden treasure. Power - up is also a theme, like Sonic getting new abilities to fight stronger enemies.
A common theme is adventure. Both Sonic X and Sonic Underground are about Sonic and his friends going on exciting adventures, and this is often carried over into the fanfiction. For example, they might be on a quest to find a powerful chaos emerald or save a new world from an evil villain.