Man, I get why you're asking—Azriel is just one of those characters who inspires some truly incredible writing, and finding the good stuff can be a mission. My absolute top spot is Archive of Our Own. The tagging system is a lifesaver; you can filter for exactly what you want, whether that's pure fluff, intense angst, or something decidedly spicier. The quality there is consistently high because writers take their time, and the community feedback loop is strong.
I also lurk on Tumblr more than I probably should. It's less organized, sure, but some of the most atmospheric, character-deep drabble comes from there. You follow a writer for one good Azriel piece and suddenly your entire dash is filled with gems you'd never find through a normal search. It requires more digging, but the payoff feels more personal, like you're in on a secret.
For a very specific vibe, I sometimes check out dedicated Sarah J. Maas fan forums. They're quieter these days, but the archives hold some classic, long-form stories that really explore his shadowsinger lore in ways newer platforms sometimes gloss over.