Yes, there are some great ones. You can start by looking on fanfiction platforms like Archive of Our Own. There, you might find stories that explore Xander Harris in the context of Tyranids in really creative ways, from him facing off against them in epic battles to more unique interpretations of his character's interaction with the Tyranid lore.
In Zerg fanfic, Xander Harris is often depicted as brave. He's not afraid to face the unknown and dangerous Zerg. For example, in many stories, he will be the first to step forward when the Zerg appear.
Well, it could be about a crossover where the characters Xander Harris and Methos from their respective fictional universes interact. Maybe they team up to face a common enemy or go on an adventure together. Without reading it, it's hard to say for sure.
What makes Xander Harris Spartan fanfic interesting is that it allows for a lot of creativity. Fans can take Xander's character and place him in a completely different setting, that of the Spartans. We can explore how he might gain new skills, make new friends or enemies, and change as a person. The fanfic can also play with the idea of time travel or alternate universes if it wants to. There are no real limits to how the story can be told, and seeing Xander in a Spartan context, whether it's in the middle of a battle or trying to understand their social structure, is always fascinating.
A common theme is family. Since Joyce is a mother figure in the Buffyverse and Xander often lacks a stable family environment, fics might explore how Joyce becomes a surrogate mother to Xander. Another theme could be protection. Xander might feel the need to protect Joyce from the various supernatural threats in Sunnydale, and this can lead to some intense and emotional storylines.
One popular Xander Harris Spartan fanfic could be 'Xander's Spartan Adventure'. It might involve Xander in some epic battles and his journey within the Spartan world. But to find more, you can check out fanfic platforms like FanFiction.net or Archive of Our Own. There are often many different takes on this concept by various authors.
One idea could be a crossover with the 'Buffy the Vampire Slayer' and 'Supernatural' universes. Xander Harris could team up with the Winchester brothers to fight demons that are a threat to both their worlds. Another idea is a crossover with 'Doctor Who'. Xander could find himself on the TARDIS and have adventures across time and space. A third idea might be a crossover with 'Harry Potter'. Xander could visit Hogwarts and help the students there deal with a new kind of dark magic that is related to his experiences in Sunnydale.
Well, the plot might involve Xander Harris being chosen as a Green Lantern in an alternate universe. He then embarks on a journey to understand the Green Lantern Corps' ways and ethics. Along the way, he could meet other well - known Green Lanterns and learn from them. At the same time, he might face villains who are specifically targeting him because he's a new and inexperienced Lantern. This would force him to grow and develop his skills quickly.