29 Apr 2009 at 17:51 - 8
As other users said, some will continue to flood the economy (birthday ones) while others will trickle in (mallyx, traveller ones, polar bear) While others may or may not ever be added again (celestial ones every 12 years) While others are unlikely to ever be added again (ceratadon, asura, kuunavang, kanaxai etc)
But who really knows.