Well, 'vector' could be anything from a mathematical concept used in a really unique and nerdy fanfiction way, to a character's name. And 'vanilla' might imply a simple or traditional type of story within the fanfiction realm. Maybe it's about a vector - like entity in a rather ordinary or classic - styled fictional situation, but again, it's really hard to say for sure without reading it.
I'm not familiar with any 'vector x vanilla fanfiction' works, so unfortunately I can't recommend any. You might try searching on specialized fanfiction websites or forums where fans of that particular genre or concept might be able to point you in the right direction.
A possible theme is transformation. Maybe the 'vector' undergoes some sort of change due to the presence or influence of the 'vanilla lemon'. For example, if 'vanilla lemon' has some magical properties, it could transform 'vector' in a way that affects the story's plot and the relationships within the story. Another theme could be discovery. The 'vector' might discover new things about themselves or their world because of their encounter with the 'vanilla lemon' concept.
One popular theme could be friendship. In vector and vanilla fanfiction, characters might form strong bonds of friendship, facing challenges together and growing closer. For example, they could be on a journey to discover a new world or solve a mystery.
First, get to know the characters well. Read the original source material about vector and vanilla if there is any. This will help you understand their personalities, motives, and backstories. Then, come up with an interesting idea for a story, like a 'what if' scenario. For example, what if vector and vanilla were transported to a different time period?
I'm not sure specifically which 'vector and vanilla lemon fanfiction' is good. You could try searching on popular fanfiction websites like Archive of Our Own (AO3). They have a large collection of fanfictions, and you might be able to find something related to these topics by using relevant keywords in their search bar.
One great yuma x vector fanfiction could be a story where they embark on an adventure together in a magical realm. They might face challenges and rely on each other's unique abilities to overcome them.
One popular Cream x Vanilla fanfiction is 'A Sweet Bond'. It beautifully portrays their relationship in a very heartwarming way. The author does a great job of showing how they interact and support each other.
You should also consider their personalities. Yuma is often brave and determined, while Vector has his own charm and intelligence. Use these traits to create interesting interactions between them. For example, you can have Yuma be the one to initiate a dangerous mission, and Vector use his smarts to plan it out. And don't forget to add some conflict, like an external enemy or an internal struggle within the relationship.