Archive of Our Own has been my central hub for years because of its incredibly granular tagging system. It's not just about having a massive number of fandoms; it's about the community-driven curation that happens through tags. You can filter by relationship, character, trope, rating, even word count. The downside is the initial learning curve – navigating all those tags feels like learning a new language, but once you do, the precision is unmatched. For less popular pairings or super niche fandoms, AO3's search functionality digs up content that would be impossible to find elsewhere, like that obscure '90s cartoon you thought only you remembered.
Reddit is weirdly effective, but in a completely different way. It’s messy, decentralized, and you have to know where to look. Subreddits dedicated to specific ships or fandoms often have pinned 'fic rec' threads where fans have essentially crowd-sourced the best works. The quality can be hit-or-miss since anyone can post, but the upvote/downvote system surfaces the community favorites. It’s less about a formal curated list and more about tapping into the collective memory and passion of a very active, very specific group of people. I found my all-time favorite 'Good Omens' slow-burn epic through a three-year-old Reddit thread that I stumbled into via Google.