A new post is made on this thread every time a new creature release is made. Depending on the creature in question the post may, at first, be quite vague, in order for people to be able to figure out what has been released and where. The details of the creatures will be filled in eventually, though.
The purpose of this thread is to also serve as a quick reference guide for release dates and creature numbers. Discussion of the creatures is still encouraged to be held in each creature's thread over at the Community Discussion.