I'm not sure specifically which 'lysa arryn lemon fanfiction' stories are out there. But generally, in fanfiction, it could explore different aspects of Lysa Arryn's character, perhaps her relationships in a more creative and uncanonical way.
Well, fanfiction often takes the existing character like Lysa Arryn and twists it. In this case, the 'lemon' might imply some romantic or spicy elements. However, finding good ones depends on which fanfiction platforms you search on. Some might be on Archive of Our Own, but it's a matter of sifting through to find the really interesting ones that do justice to the character of Lysa Arryn.
One interesting fanfiction could be about Lysa Arryn's early life in the Vale before the events of the series. It might explore her relationship with her family and how it shaped her into the character we see in the show. Another could be a what - if scenario, like what if Lysa Arryn had allied with a different house instead of the Lannisters. There are also fanfictions that focus on her relationship with Littlefinger in more depth, showing the manipulations and her emotional turmoil in that relationship.
In fanfiction, Lysa Arryn could be paired with Varys. Varys is known for his web of spies and political maneuvering. A story with them together could involve Varys trying to use Lysa for his own political ends in the Vale or Lysa trying to outwit Varys. Another great pairing could be with Brienne of Tarth. Brienne's sense of honor and Lysa's more self - serving nature could create an interesting dynamic. They could be in a situation where Brienne has to protect Lysa or Lysa has to decide whether to trust Brienne. And of course, Tyrion Lannister could be paired with her. Given Tyrion's intelligence and Lysa's paranoia, a fanfiction exploring their encounters and how they interact could be full of drama and unexpected twists.
Archive of Our Own (AO3) is a good place to start. It has a wide range of fanfiction, and you can search for Lysa Arryn - related works there. Just be sure to use the correct tags.
I'm not sure specifically about 'lysa arryn x jaime' lemon fanfiction. Fanfiction can be quite diverse, and it might be difficult to find good ones of this particular pairing. You could try searching on some popular fanfiction websites and look through the reviews to find well - received stories.
Another theme might be redemption. Jaime is often seen as a character in need of redemption, and his relationship with Lysa could be a way to explore that. Maybe through their connection, he starts to make amends for his past actions, and they both grow as characters. Also, loyalty could be a theme, as they both have loyalties to different houses and people in the story.
One good place to start looking for jaime x lysa fanfiction is on Archive of Our Own (AO3). There are many different stories there that explore this pairing in various ways. Some might focus on their relationship in an alternate universe setting, where they meet under different circumstances than in the original source material. Another option could be to check out fanfiction.net, which also has a wide range of works. However, the quality can vary greatly, so it's important to read the reviews and summaries before diving in.
There isn't a great deal of information about Arryn Blackfyre in the 'Game of Thrones' universe that is widely known. However, if we consider the context of the Blackfyre family in general, they were always a threat to the ruling Targaryens. Arryn Blackfyre might have been involved in the various political machinations and military campaigns that the Blackfyre family launched over the years. He could have been a key figure in their attempts to gain support among the lords of Westeros, perhaps using his charm or military prowess. But without more details from the books or other official sources, we can only guess at his significance.
One interesting fanfiction could be about Jon Arryn's son surviving in secret and emerging to claim his father's legacy. He might have been hidden away by a loyal servant and grows up in exile, learning the ways of the world far from the politics of King's Landing. When he returns, he causes a stir as he tries to uncover the truth about his father's death.
It could lead to a whole new power dynamic in the story. Lysa's character might become more influential or vulnerable depending on how their relationship develops.
If Lysa loved Jon, it might cause a lot of drama and complications. It could affect the relationships with other characters and potentially alter the course of events.