One popular theme is the exploration of their relationship's development. Since they have a complex relationship in the original work, fanfics often delve into how they grow closer. Another theme could be dealing with jealousy, as other characters might be involved in their story arcs.
Another option is to check out Tumblr. There are many fanfic communities on Tumblr. You can search for 'Grey x Juvia fanfic' in the search bar. Sometimes, bloggers will post their own fanfics or recommend ones they've read. But again, Tumblr has its own content policies, so not all explicit or adult - themed fanfics may be available or easily found.
Social media groups related to Fairy Tail can also be a source. For example, on Facebook or Reddit, there are groups dedicated to the series. You can post a query asking for Grey and Juvia lemon fanfiction there. However, make sure to follow the group rules while doing so.
The popularity might be due to the chemistry between Grey and Juvia in the original Fairy Tail series. Their relationship is complex and full of potential for romantic and spicy scenarios, which are often explored in lemon fanfictions.
One great 'grey and juvia fanfiction' is 'A Bond Beyond Magic'. It beautifully explores their relationship's development. It shows how they support each other during tough times in the magical world.
Some fanfictions that stand out are 'Juvia's Melody for Grey'. In this, Juvia uses her water magic in a musical way to express her love for Grey, which is a really creative concept. 'Grey's Hidden Feelings for Juvia' is also great. It goes deep into Grey's mind and shows how he's gradually falling in love with Juvia, even though he's a bit of a tsundere about it. 'Grey and Juvia: A Fairy Tail Love Story' is a more classic - style fanfiction that just tells their love story in a very engaging way.
Well, there's 'The Ice and the Rain'. This fanfic focuses on how Juvia's unwavering love starts to chip away at Grey's cold exterior. It has some really cute moments between them, like when Juvia tries to cook for Grey and it's a total disaster but Grey still appreciates the effort. Then there's 'A Shared Future' that imagines their future together, with both of them facing challenges side by side as a couple. 'Love in the Guild' is also a good one, showing how their relationship develops within the context of the Fairy Tail guild.
I'm not entirely sure specifically as it could be a very fan - created concept. But generally, if it's a fanfic involving Natsu and Juvia, it might be about their relationship in a new, fictional scenario created by the fan writer. It could include adventures they go on together, or perhaps how their personalities interact in different situations.
To write a Grey x Juvia fanfiction, start by thinking about the setting. You could set it in the Fairy Tail guild, or in a new, magical land. Next, focus on their relationship dynamics. Grey is a bit reserved, so you need to show how Juvia breaks through his barriers. You can also include other Fairy Tail characters as side characters to add more depth. For the plot, it could be a mystery they solve together. Write dialogue that reflects their personalities. Juvia's lines should be full of love and Grey's a bit more gruff but with underlying affection.
You can start by looking on FanFiction.net. It has a large collection of Fairy Tail fanfics, including many focused on Grey x Juvia. Archive of Our Own (AO3) is also a great place. It has a well - organized tagging system, so you can easily find Grey x Juvia stories. Another option is Wattpad, though the quality may vary more there compared to the other two platforms.