I think that this is the most complete set of x readers out there

When Gumball's new experiment goes awry, it leads Fionna and Marshall on an unexpected journey together, forever entangling their futures . Potions, broken hearts and journeys to unknown lands. Life and death hangs in the balance when their boundless love becomes their only lasting connection. ((PG13)) My own fanfic of Adventure time with Fionna and Cake. It has adventure and our favorite Fiolee romance. Enjoy :) (i apologize now for any grammatical errors i missed, like a surprising amount of lack of capitalization in the beginning... ;)