What are some interesting plot ideas for a Glee Starkid crossover fanfiction?

One idea could be a singing competition between the Glee club and the students from Victorious. They could meet at a national music event and initially be rivals, but then start to collaborate and learn from each other's styles. For example, the Glee club could teach the Victorious crew about more traditional musical theater numbers, while the Victorious students could introduce the Glee club to more modern pop and hip - hop influenced performances.

One plot idea could be that the Shadowhunters need to find a way to defeat a powerful demon that can only be weakened by a special type of music. So they seek out the Glee club. The Glee club members are hesitant at first but then realize the importance of their role. Another idea is that a spell gone wrong in the Shadowhunters' world sends some of their key characters to the Glee club's world. There, they have to adapt to high school life while also trying to find a way back. And the Glee club helps them blend in and in return, they learn about the Shadow World.

One idea could be a singing competition where the groups from both 'Pitch Perfect' and 'Glee' participate. They could start off as rivals, but then gradually learn from each other's styles. For example, the Barden Bellas could teach the New Directions some of their a cappella arrangements, while the New Directions could introduce more pop and show - tune elements to the Bellas.

One idea could be that some of the Glee characters visit Mystic Falls for a singing competition. While there, they get caught up in the vampire drama. Maybe a vampire takes a liking to Rachel's voice and wants to turn her into a vampire so she can sing forever. Another plot could involve the vampires using the Glee club as a cover to hunt during their events.

One idea could be that the characters from Glee find themselves in Central City during one of The Flash's battles. Maybe they get caught in the crossfire and The Flash has to save them while also dealing with the meta - human threat. For example, Rachel could be singing on the street when a meta - human causes chaos nearby.

Another concept is that a villain from The Flash's world uses the power of music (inspired by the Glee club's performances) to create chaos. The Flash teams up with the Glee club to reverse the effects of the music - based villainy. The Glee kids could use their knowledge of harmony and rhythm to counter the negative musical energy, while the Flash uses his speed to stop the physical manifestations of the villain's attacks.

One idea could be that the Glee club is invited to perform at a big event in National City where Supergirl is also present. They could end up teaming up to save the day when an alien threat targets the event. The Glee kids' unique talents could be used in unexpected ways, like using their voices to disrupt an alien's sonic weapon.

One plot idea could be that a character from Flash, like Barry Allen, somehow gets zapped into the Glee universe. He could be confused by all the singing and dancing at first, but then use his speed to help the Glee club prepare for a big competition in a very short time. For example, he could quickly gather all the necessary props or help the members with their choreography by demonstrating moves at super - speed.

One idea could be that a character from Glee, like Rachel Berry, ends up in the world of White Collar and gets involved in one of Neal's art - related cons. Maybe she uses her singing talent to distract people during the heist.

One idea could be exploring the backstories of the characters in more depth. Maybe there are hidden pasts that influence their actions in the 'gloaming glee' world.