I only just found this out, but for the Oblivion Vampire Cure quest, you had to seek out a Witch who was believed to be the last Glenmoril Witch. You can actually find an entire Cove of them - although they are Hargravens - in Skyrim. I just thought this was really interesting, and nobody seems to have realized this

What's even funnier is that their heads are required for curing Lycanthropy. Intentional on Bethesda's part i'm guessing?
Just thought i'd share
~Undeaddragon