I'll be expecting any creature with fur to have large amounts of winter fluff.
There is no fixed theme for the community collab. However, this year, the background will be a bit snowy, so if you want to bundle your OC up in a scarf, some warm socks, a winter hat, coat, etc, please do so! Although that is totally optional — ponies do have a natural fur coat, after all! (as do donkeys, while griffons have down, etc)
Derpibooru costs over $25 a day to operate - help support us financially!