I think Pony Head would be an interesting character to pair with Dark Marco. She has a bold and sassy personality that could contrast with Dark Marco's darker, more brooding nature. Also, Marco's parents could be paired with him in fanfiction. Their reactions to his transformation and how they try to help or deal with him could add an emotional and family - centered aspect to the story.
One idea could be exploring how Dark Marco's powers change his relationships. For example, his friends might be afraid of him at first. Another could be him using his powers to fight new, more powerful enemies in the SVTFOE universe.
Well, in SvTFOE Marco x Kelly fanfiction, often it explores their relationship in different ways. It might show how they interact in various situations that are not fully explored in the original series. Maybe it focuses on their shared adventures and how they grow closer through those experiences.
Power is also a big theme. His vampire powers bring new abilities and responsibilities. He might struggle with controlling them or using them for good. There's also the theme of secrecy. Since being a vampire is not a normal thing in the SVTFOE world, he has to keep it a secret, which adds a lot of tension to the stories.
One popular 'SVTFOE Vampire Marco' fanfiction is 'The Vampire's Mark'. It has an interesting plot where Marco discovers his vampire side and has to deal with the challenges that come with it in the SVTFOE universe.
One common theme is the exploration of their different natures. Marco is often seen as the more normal one compared to Eclipsa's otherworldly and powerful self. Another theme is friendship. They come from different backgrounds, so how they become friends or more is a big part of these fanfictions. Also, there's the theme of discovery. Discovering each other's worlds, secrets, and powers.
One common theme is probably adventure. Since the original show has a lot of adventure elements, the fanfiction might continue that trend with Marco and Kelly. Another could be love and relationship growth, as fans are interested in seeing how their relationship evolves.
Fanfiction.net is also a great place to find such stories. There are many authors who post their works about Star and Marco there. Just use the search function and type in relevant keywords like 'Star vs. The Forces of Evil Star and Marco' to find what you're looking for.
One great 'svtfoe star and marco fanfiction' story could be those that explore their adventures in different dimensions. For example, a story where they accidentally end up in a dimension full of musical creatures and have to use their friendship and unique skills to find their way back home.
One popular 'svtfoe marco x eclipsa fanfiction' might be 'The Unlikely Bond'. It explores an interesting relationship between Marco and Eclipsa. Another could be 'A New Alliance' which delves into how they team up in a unique situation. There's also 'Unexpected Encounters' that focuses on their chance meetings and the development of their relationship from there.