What uncommon trope/setting/idea do you wish to see more of in fanfiction?
I wish there were more fics with Jayce giving up or losing Viktor, and then beginning a relationship with Mage Viktor. You Are But You Aren't by L1av is a great one because their personalities mesh, but their histories clash which could work so well for drama. I'm actually working on a post-canon modern-AU story in my notebook with that exact dynamic and let me tell you, it's filled with potential.
Another one that I'm shocked people haven't really written about is Viktor being put on trial for war crimes against Piltover/Viktor's legacy is ruined and re-written by biased historians. This one is primed for drama because Piltover's classist attitudes could be amplified by the trauma of the war, but maybe Ximena and Caitlyn would be defending him as "the Viktor that they knew for 7 years".