so I've got a decent sense of the landscape. The most popular pairing by a mile is just Gura and Amelia, often tagged as Amelia Watson/Gawr Gura, no frills. It's the classic dynamic: the chaotic gremlin shark and the time-traveling detective, with all the expected tropes—roommate AUs, office settings, coffee shop meet-cutes, that sort of thing.
A slightly less common but definitely persistent variant is the poly pairing, usually tagged as Ina'nis Ninomae/Amelia Watson/Gawr Gura. This often appears in longer fics where Ina's the grounding, calm center between the two more energetic and chaotic forces. It feels like a natural extension of their group dynamic from the streams.
You'll also occasionally see crossover ships bleed in, especially if an author is known for a particular fandom. Things like Gura/Amelia but in the 'Final Fantasy VII' universe, or as characters from 'The Magnus Archives'. It's niche, but it happens when a writer has two hyperfixations that collide.
The appeal, I think, is in the contrast. Amelia's often written with this frustrated, methodical energy, and Gura brings this uncontainable, childish glee that disrupts her perfectly ordered world. It's a classic opposites-attract setup that's incredibly fertile ground for both comedy and surprisingly tender moments. People really lean into the idea that Gura doesn't just annoy Ame, she fascinates her in a way nothing else can.