A third plot idea could be a 'what if' scenario. What if they had their first time under the influence of a meta - human power that made them more open and vulnerable? This could lead to some interesting character exploration as they deal with the consequences of this unexpected event. They would have to navigate their feelings and the changes in their relationship while also dealing with the potential danger of the meta - human's power still being out there.
One idea could be them facing challenges in their married life due to Oliver's vigilante duties. Maybe Felicity gets worried every time he goes out at night. Another could be them planning to start a family and all the joys and concerns that come with it. Or perhaps they take a trip together and encounter some old enemies during their journey.
Well, a plot could revolve around Felicity having a difficult pregnancy. Oliver then has to balance his duties as the Green Arrow and being a supportive partner. They could also have a story where they are trying to prepare for the baby's arrival while dealing with a new villain in Star City. This villain could be targeting pregnant women, making Felicity a prime target. So, Oliver has to stop the villain while also taking care of Felicity.
One idea could be that Oliver and Felicity's baby has some sort of unique meta - human ability that they have to protect it from those who would use it for evil. Another could be the baby getting kidnapped and Oliver and Felicity having to team up with their old Arrow - team friends to get it back. They could also face challenges in raising the baby while still being vigilantes.
One common plot idea is exploring their life after the events of the show. For example, how they handle raising a family while still being involved in the vigilante world. Another idea could be alternate universes where they meet under different circumstances, like Felicity being a superhero herself and Oliver being a tech genius who helps her.
Perhaps there's a villain who targets Felicity because of her pregnancy. This villain could see the baby as a way to get back at Oliver. So, Oliver has to go to great lengths to keep Felicity hidden and safe. Meanwhile, Felicity could be using her intelligence to find a way to outwit the villain from her hiding place, all while dealing with the physical and emotional changes of pregnancy.
Another plot could revolve around the challenges of raising a baby in their dangerous world. They have to constantly protect the baby from their enemies. Maybe there are villains who try to kidnap the baby to get to Oliver or Felicity. So they have to set up a super - secure hideout and enlist the help of their friends like Diggle.
In certain fanfictions, Felicity and Oliver's first kiss is set against a backdrop of a beautiful, moonlit night. They've been having a deep conversation about their fears and hopes. As they look into each other's eyes, the chemistry between them becomes irresistible. Oliver slowly moves closer, and Felicity meets him halfway. Their first kiss is soft and sweet, a moment that both of them have secretly been longing for, and it marks the start of a new chapter in their relationship.
There might be a fanfiction where they time travel to the future. In this story, they could see the consequences of their current actions and have to figure out how to change things in the present to avoid a dark future for Star City. They might encounter future versions of themselves or their friends, which would add an interesting dynamic to the story.
One popular theme is 'alternate universe' where the story is set in a different world from the original Arrow series. For example, they could be in a high school setting or a fantasy world.
One possible scenario is that they are in the middle of a fight against a common enemy. In the chaos, they get separated from the rest of the team. As they reunite, the relief and the underlying feelings they have for each other bubble to the surface, leading to their first kiss. Another could be at a celebration. After a big victory, everyone is in high spirits. Felicity and Oliver find themselves alone for a moment, and the joy of the moment and their closeness prompt the kiss.