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.
You can start by looking on fanfiction.net. It has a large collection of fanfics, including many about Grey and Juvia. Just search for their names in the search bar.
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.
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.
In a 'Juvia Gets Drunk' fanfiction, Juvia would most likely interact with the members of Fairy Tail. She might start bothering Natsu, asking him silly questions like if he can really breathe fire while drunk. She could also interact with Happy, and they might get into some sort of funny exchange, like Juvia trying to teach Happy a new song she made up in her drunken state. And of course, she'll interact with Cana. Cana being the drinker she is, might find Juvia's drunk behavior either hilarious or relatable and they could have a long chat about different kinds of drinks.
Their relationship would likely become more serious. They would have to think about not just themselves but also their baby. There would be more commitment and responsibility between them.
Gray could be a great addition. Since Gray has a history with both Juvia and Lyon, his presence can add a lot of drama. For instance, his reaction to Juvia and Lyon getting closer could range from jealousy to acceptance, which would create different story arcs.