I have two suggestions for consideration as you start planning a new round of Halloween and Christmas dragons:

1. For Halloween, a candy themed world event. Dragons could be candy corn, jawbreakers, caramels, etc. This could also work as an Easter event.

2. For Christmas, have all dragons released in December be based on the twelve days of Christmas. It would be challenging to design, but I have every faith that the artists could do a fantastic job! I would certainly knock myself out trying to collect the full set; in fact, I'm pretty sure that all my itunes gift cards will end up going to DS...