There are class emblems you get for creating a certain class (i.e. create a titan and you get the Officer Crest). Then there are the emblems for each sub class. For example "A Song for the Sun" quest on the warlock will net you the emblem for the Sun singer class. The "Legend of the X" quest gives you a blue class item once completed and is completed by reaching level 30. Which emblems specifically are you trying to get?