Hellsing, Vampire Knight Recommendations
Both anime are about vampires. Some vampires wish to do harm and have some sort of evil plan but the main character tries to stop them. In Vampire Guilty it takes a while for the action to start also because this anime is about more than just the action and bloodshed. It also involves romance and therefor Vampire Knight is more a shoujo while Hellsing is more a shounen.
Both animes include blood and vampires. "Royal" vampires and the "unpure" vampires, who are to be eliminated, are present in both series. The main heroines, Yuuki and Seras Victoria tend to have similar personalities.