Blood Scion, Vampire Lord and Blood Scion, Bloodknight: There are plenty of existing Blood Scion, Bloodknight, and Vampire Lord appearances in the game. They all use pretty similar models and animations, too. There could easily be a Skill Style to swap between these models.

Vampiric Drain, Void — A Void-themed style so you can roleplay as a Voidblooded vampire who feeds on the Void.
Mist Form, Harrowstorm — A Harrowstorm-themed style so you can roleplay as a vampire in the Gray Host. The mist around you can have red lightning.

---

Werewolf Transformation, Undead and Werewolf Transformation, Skeletal: Both of these models use the same animation set as the player werewolf, so this should be an easy model swap.

Infectious Claws, Necrotic and Hircine's Bounty, Necrotic — Blue-colored styles to make your werewolf appear to use necrotic energy. Pair this with the Skeletal style mentioned above to really look like one of the risen dead.
Pounce, Harrowstorm — A Harrowstorm-themed style so you can roleplay as a werewolf in the Gray Host. The dust that gets kicked up can have red lightning.

---

Flame Skull, Hollowjack — Replaces the skull with a fiery jack-o-lantern pumpkin. Great to pair with the Hollowjack Rider mounts:
Sacrificial Bones, Zombie and Skeletal Mage, Zombie — Replaces the skeletons with zombies who have a little more flesh on their bones.