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.
Rachel Berry from 'Glee' would be a key character. She is so ambitious and has a strong vision for music. In a crossover, she could clash with Aubrey from the Barden Bellas over leadership and musical direction. This conflict could drive the story forward as they both try to prove their way of doing things is the best.
Competition is also a theme. Since both shows involve elements of competition, fanfictions might focus on the lead - up to a big competition, the rivalries, and how the characters overcome challenges. In Pitch Perfect, it could be about the Bellas preparing for the ICCA championships, and in Glee, it could be about the glee club competing in regionals or nationals.
You can start by looking on fanfiction websites like Archive of Our Own (AO3). It has a large collection of Pitch Perfect and Glee fanfictions. Many fans contribute their works there, and you can search by tags such as the characters you like or the type of story you're interested in, for example, a romantic story between two main characters from Pitch Perfect or Glee.
Beca and Finn from 'Glee' could be a great pair. Beca is this edgy, music - loving girl in Pitch Perfect, and Finn is the football player - turned - singer in Glee. Their different backgrounds and approaches to music could lead to an interesting dynamic. They could learn from each other and maybe even fall in love while working on a musical project together.
A crossover with 'High School Musical' would also be cool. Picture the Pitch Perfect girls and guys going to the same school as the High School Musical characters. There could be a big musical showdown where the two groups have to combine their talents. The Pitch Perfect crew's edgy acapella style might clash and then blend with the more traditional musical theater style of High School Musical, leading to an amazing performance.
Perhaps there's a parallel universe where the Twilight world and the Pitch Perfect world collide. In this universe, the characters from both stories start to swap abilities. The Bellas find themselves with vampire - like strength and speed, while the Cullens develop an uncanny ability to sing in perfect harmony. Bella and Fat Amy become friends and try to figure out how to get their respective worlds back to normal while also using their newfound combined skills to put on the best a cappella show ever.
One common theme is competition. Whether it's against the new group they cross over with or in a new setting, the idea of competing in music is always there.
Fat Amy and Emmett would be a hilarious pairing. Fat Amy's over - the - top and fearless personality combined with Emmett's big - hearted and strong - willed nature. They could get into all sorts of comical situations. Maybe they start a side - project within the a cappella group or in the vampire world. Fat Amy could make Emmett laugh like no one else, and Emmett could protect Fat Amy from any threats, whether it's from jealous vampires or rival a cappella groups.
It also encourages creativity within the fandom. Writers of this fanfiction might come up with unique storylines and characterizations that can inspire other fans. For example, they could create a whole new backstory for Beca and Chloe's relationship that makes the kiss even more meaningful.