Just for clarification, there are two different kinds of eggs available ingame.
Unhatched eggs contain all dragons you can tame ingame and are the ones DalekFell mentioned and the oney you actually need to hatch.
The other kind are soulgaze eggs. A soulgaze item can drop from every dungeon boss at a certain chance and after activating the item you get one dragon egg from a selection of five possible dragons for each dungeon. The dragons you can get that way are all former cash shop only dragons.
-> here's a list of all currently available cash shop dragons through soulgaze items. It's in german since I can't find an updated english thread but at least you can see all dragons.^^°