Arcane reaction fics? That's a surprisingly specific niche to ask about. I mostly see them tagged under 'Arcane (TV 2021)' on AO3, focusing on the fallout from a big emotional moment or plot twist. The ones sticking with me lately aren't necessarily the epics; it's the quieter, introspective pieces. There's this one called 'Silt in the Pilt' that lives rent-free in my head—it's all about Caitlyn and Vi dealing with the aftermath of the bridge scene, but through the lens of mundane police work and shared silences. The author captures how a reaction isn't always explosive; sometimes it's the slow seep of grief into routine.
Honestly, a lot of the popular ones right now are Jinx-centric, exploring her fractured psyche after the finale. They can be hit or miss. Some just rehash the show's angst, but a few, like 'Echoes in the Still Air,' use the reaction framework to imagine a path toward a fragile, non-linear recovery, with Vi's clumsy attempts at care as the catalyst. It feels painfully real, the way it handles the awkwardness of loving someone you no longer fully know.
If you're burnt out on Piltover, I'd suggest looking for crossover tags. Saw a weirdly compelling one blending 'Arcane' with 'Dishonored,' where Corvo's arrival in Zaun forces reactions from the entire cast that the original show never could. The worldbuilding shifts the character dynamics in fascinating ways.