If you can think of it, it probably has a Fortnite collaboration. The battle royale has had skins from some of the biggest franchises in the world, and it is showing no sign of stopping these crossovers anytime soon.
According to a recent episode of the Xbox Era podcast, a slew of new collabs and skins are coming to Fortnite at some point in the future. These include: Doctor Octopus from Spider-Man, a Final Fantasy VII: Rebirth collaboration, He-Man and Skeletor skins, Peacemaker, Robin, X-Men characters, the Fantastic Four, and a One Piece crossover.
<social>https://www.youtube.com/watch?v=cRTV64lboD0</social>
It's likely that One Piece (and potentially Final Fantasy VII: Rebirth) will have special events tied to them, giving players special powers in-game which will likely break the meta for a few weeks before they disappear.