Can I purchase additional monsters or heroes for the CR board game? And if so, do they come with their stat cards? Just want to get the most out of the game as possible.
A Gray Hag promo exists, but it was a fairly limited release.
Legend of Drizzt is the latest game in the series and, according to the product information page, is also fully compatible with both other games.
I don't know about add-ons for Castle Ravenloft, but I know wizards made ANOTHER D&D Adventure System board game called Wrath of Ashardalon.