There's a fanfiction titled 'Merlin and Cassandra: A Magical Alliance'. In this story, they join forces to face a common enemy, and their unique powers complement each other. It's really interesting to see how they interact and grow together in the face of danger. Also, 'The Secret Meetings of Merlin and Cassandra' is a good read, which focuses on their secret rendezvous and the development of their relationship.
Another theme is destiny. Given that both characters are often associated with prophecies in the original lore, fanfictions tend to play with the idea of their fates being intertwined. They might be destined to meet, or their actions together are part of a greater plan for the world. For instance, some stories show that they are the key to restoring balance to a world thrown into chaos by dark magic.
Well, 'Cassandra: The Unseen Struggles' is a fanfiction that's worth reading. It shows the internal battles Cassandra faces, her doubts, and how she overcomes them. 'In the Shadow of Cassandra' is about how other characters perceive her and the impact she has on them. Then there's 'Cassandra's New Beginnings' which is set after the events of the game and shows her taking on new challenges and roles.
I also like 'The Inquisitor and Cassandra: A New Chapter'. This fanfiction explores a different take on their relationship. It begins with a misunderstanding between them but as the story progresses, they start to see each other in a new light. The author does a great job of building up the tension and then resolving it in a satisfying way.
One great place to start looking for such fanfiction is Archive of Our Own (AO3). There are numerous stories there that feature a female inquisitor and Cassandra. You can search using relevant tags like 'female inquisitor' and 'Cassandra Pentaghast' to narrow down the results.
Some Cassandra x Varian fanfictions that are worth checking out include those that explore their different personalities and how they complement each other. For example, Cassandra's strong - willed and often head - strong nature contrasted with Varian's inquisitive and sometimes naive side. Stories that play on this dynamic can be really engaging. You can also look for fanfictions that are set in alternate universes, like a steampunk version of their world where they might have different roles but still end up drawn to each other.
Well, 'The Lost Years of Merlin' is an excellent piece of Merlin fanfiction. This story imagines what Merlin was doing during the years that were not shown in the series. It has a lot of details about Merlin's growth as a wizard and as a person. Additionally, 'Magic Unbound' is a good one. It plays with the idea of magic being more free - flowing in Camelot and how that would change the dynamics between Merlin and the other characters.
Sadly, I can't directly recommend any Cassandra Methos fanfic. But here's how you can find some good ones. First, use the search function on fanfic platforms and look for keywords like 'Cassandra Methos' and sort the results by popularity or rating. Another option is to follow fanfic writers who are known for writing about similar characters or in the same genre. They might have written or know of some great Cassandra Methos fanfics.
Another interesting one is 'The Hidden Enclave'. It takes a different approach by exploring a part of the Shadowhunter world that was only briefly mentioned in the original works. The author does a great job of expanding on this concept and creating a whole new adventure within the familiar setting.
There's a fanfic called 'Cassandra and Rachel's Adventure'. In this, they embark on a journey together through a magical land. It's full of vivid descriptions and the characterizations of Cassandra and Rachel are really well - done. They face challenges and their friendship grows stronger as a result.
There's a fanfic called 'Apollo and Cassandra: The Forgotten Bond'. In this one, they are reunited after centuries apart due to some magical interference. It shows their initial confusion, then the slow rekindling of their connection. Also, 'The Trials of Cassandra with Apollo' is interesting. It takes them through a series of challenges that test not only their relationship but also their individual powers.