The Macellarius are just disgusting to look at, being grotesquely swollen and obese — and they just get fatter as they age. They seem to be so polite, so genial and then, when you least expect it, they snap at you like the beasts they are. They hold the most disgusting banquets you could ever imagine, which sicken even other vampires — and that's before you take into account the fact that they can actually eat human flesh, and invariably become addicted to the taste of it.
The Carnival are a Daeva bloodline who are so prone to Body Horror, even if they were perfectly normal before the Embrace, that they actually get the Nosferatu clan weakness. Out of the sight of ordinary humans, they perform the Show, sights and acts so bizarre that the most depraved human freak show could only dream of it. And if you're lucky, you'll be drawn into a special performance... The Carnival calls that "the Blowoff", and it's how they find prey.
The Oberlochs are basically the antagonists of every Hillbilly Horrors film come to (un)life as clannish, weirdly incestuous vampires. They're savages, they absolutely hate "city slickers", and because of some weird quirk of their blood, they're eternal but they still age. Expect re-enactments of the famous "sucking on bloody fingers" scene from the original The Texas Chain Saw Massacre (1974).
The Sangiovanni are incestuous, necrophiliac, inbred mafia necromancer-vampires.
Let's save time and state that most of the Nosferatu bloodlines are this, but, if really curious...
The Burakumin are unnervingly, unflinchingly polite... but their take on the Nosferatu curse means that as the years roll by, they keep rotting away. Oh, and did you remember they happen to be one of the three Bloodlines that have Disciplines that let them create and commandThe Undead?
The Noctuku are monsters even to other vampires; they are plagued by an insatiable craving for not only the blood, but the flesh of other vampires. They're actually a Mythology Gag to the Niktuku of Vampire: The Masquerade, who were similar in nature.
The Rakshasha are so deformed and naturally malevolent that they believe they genuinely are demons sent to torment all who live on Earth.
The Moroi might seem like a mild example. Oh, sure, they have in-clan access to two of three physical disciplines, and the stealth discipline, and Animalism, and probably start with dots in either Nightmare or Protean with easy access to the other, and they either hunt in packs or are old and powerful enough to take on entire coteries alone, and they have murderous impulses, but they won't physically or mentally torture you for decades like your average vengeful Ventrue. Nope! If you cross them, or you're their assigned target, or you get in the way, or you learn too much, or you happen to be wandering down the street when they're hungry and one of them lacks the self control to not drain you dry, they'll just kill you. Nothing to worry about at all!
Formosae: They're like vampires, but not quite vampires. They deliberately prey on people with poor self-image because they feed on resentment and loathing; their feeding does drain away fat and leave their victim beautiful but it quickly becomes fatal. And they are themselves absolutely hideously fat.
Cymothea Sanguina: a parasitic arthropod that bores into the lower jaw and eventually replaces the tongue, slowly converting its human host into a mindless blood-drinking zombie whose guts eventually rot away and fall out (to nurture larvae), leaving them to spend their last few days alive savagely attacking anything in sight.
The Ragged Man is a parasite that grows inside vampires, sort of a repulsive combination of a tapeworm and a Chestburster.
Draugr are what happens when a vampire finally gives up on trying to maintain some level of humanity. Larvae are vampires who were made that way.