A possible storyline is that there is a threat to the world that requires both Darcy's out - of - the - box thinking and Steve's strategic mind. They are forced to work closely together, and during the process, they face many challenges. Along the way, they find that they complement each other well and a romantic relationship begins to blossom.
One interesting storyline could be Darcy and Steve teaming up for a secret mission. Steve's combat skills and leadership combined with Darcy's scientific knowledge could make for an exciting adventure. Maybe they have to stop a villain who is using some sort of advanced technology that only Darcy can understand.
Fanfiction.net is also a great place to search. There are a large number of stories on there. Navigate to the Marvel or Avengers section and then specifically search for stories involving Darcy Lewis and Steve Rogers. You might have to dig a bit through the results to find the ones that really interest you.
Another theme is friendship. They might start as friends who support each other. For example, Steve could rely on Darcy's scientific knowledge in certain situations, and Darcy could look up to Steve for his leadership and moral compass. This friendship then might or might not turn into something more romantic as the story progresses.
Their relationship could start with mutual respect. Steve would respect Darcy's intelligence and her ability to hold her own in tough situations. Darcy would respect Steve for his heroism and self - sacrifice. This respect could then turn into friendship as they spend more time together, perhaps on Avengers - related business. Eventually, friendship could grow into love as they discover more about each other's personalities and interests.
One interesting storyline could be Darcy getting involved in an Avengers mission in a scientific capacity. Since she has a background in science, she could help the Avengers figure out some complex alien technology they come across. For example, she might be the key to understanding a new weapon that an enemy is using.
A really interesting storyline could revolve around Steve Rogers' pregnancy in an alternate universe. Maybe in this universe, male pregnancy is more common among enhanced individuals. He could be part of a community of male parents - to - be. His pregnancy might also bring out a more nurturing side of him that we haven't seen before. He could start mentoring other expectant fathers, all while still having to deal with the threats that come with being Captain America.
Another common plot is a time - travel related one where the OC and Steve Rogers are sent back in time together. This could lead to all sorts of adventures, like them having to blend in with the past while also trying to figure out how to get back to their own time. Maybe the OC has some knowledge of history that helps Steve, who is already familiar with the past, in a new way.
One storyline could be that they receive a prophecy during Sharon's pregnancy that their child will have some sort of special power. This leads them on a journey to find out more about it and protect their unborn baby from those who might want to use the baby's power for evil. Along the way, they meet other characters from the Marvel universe who either help or hinder them.
One popular storyline could be them dealing with the challenges of pregnancy during a time of war or superhero duties. Maybe Steve is worried about protecting Peggy and their unborn child from his enemies.
There are fanfictions where Baby Steve Rogers meets characters from other universes in his childhood. For example, he could meet a young wizard from a magical world. The story would then be about how their different worlds collide in the most unexpected ways. It could show Steve learning about magic and the wizard learning about Steve's world of science and medicine in the 1930s. It would be a unique blend of two different fictional concepts.
One interesting aspect could be how she interprets the X - Men's powers in her fanfiction. Maybe she gives a unique take on Wolverine's healing factor or Storm's weather control. Another aspect could be the relationships she creates among the X - Men characters in her stories. It might be a fresh look at the classic friendships or romances in the X - Men universe.