The dragon cats, cats with dragon wings and bladed dragon tails, have been hiding themselves from the Clans for a very long time. When they reveal themselves to get the Clan cats to stop hunting on their territory, it changes everything. No characters from the books appear in this story.
When the Vikings made peace with the dragons, they attracted the attention of a third party they'd never seen. The Dragonwings, winged humans with bladed dragon tails and illusion powers, watched the Vikings on Berk until they were sure they could trust them. Now, a year later, the Dragonwings have come out of the shadows...
Loki/OC. Loki's lover shows up with donuts. Loki is ecstatic. Set at least a few years before Thor, possibly even decades... basically, could be set any time from when donuts were invented to the day before Thor's interrupted coronation.
A dragon enjoying and reflecting on the joys of flying in a thunderstorm.