Starter Packs - Files are separated into a Vampire or non-Vampire starter pack. Vampires become infected at the "Unbound" save. Standing stone choices may vary depending on the active DLC's.
Lycanthropy - These saves were made immediately after the Way of the Voice was completed and only involve the Companions up to your induction as a member of the Circle.
Arvak - These saves get you to the most important point in the game... ARVAK! No more lost horses, dying horses (he's already dead), stupid horses, buying horses, ect. Files are separated into Vampire or non-Vampire selections. Vampires are aligned with the Volkihar, non-Vampires are aligned with the Dawnguard.
Civil War - Civil War questline complete for both Imperial and Stormcloak. Stormcloak saves done as a vampire/Vampire Lord as appropriate. These saves were made after Arvak is acquired for Dawnguard and All DLC's.