I think Mabel could be a great character to pair with Pyronica. Mabel's positive and bubbly personality would contrast so much with Pyronica's more devious nature. It could lead to some really fun and unique stories where Mabel tries to reform Pyronica or something like that.
Bill Cipher is an obvious choice. Since they are both from the same 'universe' in Gravity Falls and seem to have some sort of connection already. Their interactions can create really interesting and often chaotic storylines.
Dipper could also work well. He's the more inquisitive and knowledge - seeking character. Pairing him with Pyronica could result in stories where he tries to figure out her secrets or they end up in some sort of battle of wits, which would be really engaging for readers.
I think a character like Leo would be great to pair with Ainsley. Leo is kind - hearted and adventurous, which can create interesting dynamics with Ainsley. Another good one could be Mia. She's smart and has a strong personality, and she and Ainsley could have some really engaging conversations and adventures together.
I think Ethan Hunt could be a great character to pair with August Walker. Their different moral compasses and methods would create a lot of interesting interactions and power struggles.
Well, adventure themes are quite common. Picture Pyronica going on a wild adventure across different dimensions that are related to the Gravity Falls universe. Also, redemption arcs can be a theme. Maybe she tries to change her evil ways in some fan fictions. And of course, there could be love - not in a typical sense perhaps, but some kind of special connection with another character.
Kuzco would be an obvious choice. Their relationship in the original story is full of conflict, and in fan fiction, they could have new adventures together. Maybe they are forced to team up against a greater evil and slowly start to understand each other better.
Brian is a great character to pair with Stewie. Their dynamic in the show is already rich, and in fan fiction, it can be taken to new levels. They can have deep conversations or get into wild misadventures together.
Naoto could be a great character to pair with Chie in a fan fiction. Naoto's detective skills and Chie's combat abilities would make them a formidable team. They could work together to solve a complex mystery in Inaba that has both a physical and intellectual aspect. Additionally, Rise could be paired with Chie. Rise's idol status and Chie's martial artist identity could lead to some unique situations. For example, Rise could ask Chie to be her bodyguard during a concert tour, and they could end up facing some Shadows along the way.
Dipper is a great choice. Their personalities are quite different, with Dipper being the curious and nerdy type and Pacifica being the rich and initially snobbish girl. Their interactions can lead to a lot of interesting storylines, like when they first met at the party and there was that instant tension.
Chat Noir would be a great pairing. Their different powers and personalities could create some really fun and exciting interactions. Chat Noir's flirty nature combined with Multimouse's more cautious approach would make for an interesting dynamic.
Goku is a great character to pair with Beerus. Their relationship in the original series is full of tension and mutual respect. In fanfiction, they could have all sorts of adventures together, like exploring new galaxies or training in unique ways.
Yoshi would be an excellent character to pair with Bowuigi. Yoshi's friendly and helpful nature can contrast or complement Bowuigi's personalities. Donkey Kong is another good choice. His brute strength can be a great counterpoint to Bowuigi's more strategic thinking. And Toad could be added for his loyalty and sometimes comical nature.