I just published the first chapter to a new Splatoon fanfic on Fanfiction.net. I call it "The Sapphire Splatoon." He's the synopsis:

Cobalt, Alani, Forest, and Rosie are a team of Inklings with great skill and even better teamwork. This is the story of their journey from just another team of Turf War battlers to an official team of the Elite Turf War League. And there's plenty of hi-jinx, drama, and even romance to be had along the way.

You can find it here: The Sapphire Splatoon