Thinking about fanfics I really liked before I figured out how to bookmark stuff on AO3, and while I found one of them...there was a Fake News FPF BDSM AU that was just brilliant, really worldbuilding heavy and surprisingly emotional for what it was, and a Glee/Hunger Games mashup (Brittana of course) that was one of the only times I've seen Brittany written as something other than comic relief, and an Animorphs/Hunger Games crossover where Cassie was trying to start a revolution with Cinna, very worldbuilding heavy, descriptive and angsty. Sometimes I wonder how anyone finds any fics they like a second time.