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 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.
One idea could be a time - travel plot where Darcy accidentally gets sent back in time and meets a young Steve and Bucky. They end up on an adventure together, with Darcy's modern knowledge helping them in unexpected ways.
Well, Steve is the all - American hero, very moral and upright. Darcy is more of a free - spirit and a bit of a science geek. Bucky has his tortured past. In a story, Darcy's light - heartedness can balance out the seriousness of Steve and Bucky. Steve can offer protection and guidance, while Bucky can share his more real - world, darker experiences with Darcy, creating a deep bond among them.
She might survive by making use of her relationships. For instance, if she has some sort of connection with Loki (maybe from past encounters), she could call out to him telepathically (if there's some sort of magic involved). Loki, being the trickster he is, could then come and rescue her. Another way is that Darcy could use her knowledge of science to create a makeshift weapon or a device that would help her escape from Hydra's clutches. She could use the materials available in her cell to build something useful.
In a fanfiction, Darcy could be wearing special glasses that allow her to swim underwater for a long time, like some kind of high - tech Avengers gadget. She could be using this ability to spy on an underwater threat. The other Avengers might not be aware at first, and there could be some comical misunderstandings.
In literature, one of the most famous Darcys is Fitzwilliam Darcy from Jane Austen's 'Pride and Prejudice'. He is a complex character, initially seen as proud and haughty, but as the story progresses, we discover his true and noble nature. He falls in love with Elizabeth Bennet, and their relationship is full of misunderstandings and growth.