Vampire: the Masquerade

More Clans
Pretty much every expansion clan gets one new discipline (except the Old Clan Tzimisce, because “fuck those guys”). When a new bloodline is written up, their bullshit new powers get written up along side them. Once a discipline got added to the pile in this way, they were in the pile – so sometimes an expansion bloodline had a discipline that was some earlier bloodline's big new thing. Like how the Nagaraja had Necromancy (which had been the Giovanni's big new thing) but also introduced Nihilistics as their own big new thing.
The expansion bloodlines also don't get nearly as much backstory and narrative focus as the main seven, and they are all officially optional (though later books pretty much assumed you were using all of the things). So by and large, these new disciplines were the biggest driver in you wanting to play any of these assholes. So if you were taken by Obscurica, Halitosis, or Petulance, you could try to convince your storyteller that you should be allowed to play one. And when enough players wanted to be one of these expansion clans, then White Wolf would make a clanbook for them and tell all the players that their characters had been incestuous corpse fuckers the entire time.
Assamites

The Assamite clan are a bunch of quasi-Muslim dark skinned Middle Easterners who are terrorists and assassins. If that sounds super racist to you... well... it's super racist. But you gotta remember that this shit came out in the early 90s when the United States hadn't spent the last 13 years occupying parts of Iraq and presidential candidates weren't debating whether to ban entry by Muslims into the country. So while the Assamites are an offensive and racist caricature, at the time they weren't part of a culture of hate but instead merely the ignorant musings of people talking about exotic lands with no knowledge and little curiosity.
Assamites are blessed with Celerity and Obfuscate, which we recall were the things given to City Gangrel as well. That was the package of disciplines you wanted if you intended to kill people in combat by hitting them with damage until they died. It let you smuggle weapons places and ambush people with Obfuscate and then attack several times during the surprise round with Celerity and then you win. This was by far the most effective combat strategy, so the fact that there are not one but two “combat themed” expansion bloodlines that get exactly that combo means that some of the authors were totally fucking lying when they said that the trenchcoats and katanas style of playing the game was not the way they did it.
Their new discipline is Quietus. Which is a mysterious grab bag of powers that don't make an sense. You can turn off noise (so you can get away with shooting people with big guns) and then you can make poisons out of your blood? It's undergone a number of revisions because honestly no one gives a single shit about this discipline except for the part where it lets you use firearms in cities without alerting the police. Assamites were created because someone wanted to have a bloodline that was “good at combat” and absolutely every single thing about them is totally subservient to that. Their backstory, their clan organization, their culture and disadvantages are all stupid asspulls to put a fig leaf over having written a clan whose entire reason for existence was to be “best at combat.” And if combat was a thing where it especially mattered if you were good at it, Assamites might even be broken.
There's pretty much no reason for this clan to be a thing. They exist because there was a game mechanical niche. If a new edition had different combat rules, they wouldn't necessarily be best at combat anymore and then they'd have nothing at all. Basically the way to look at these guys is one of the authors angrily writing a workaround to the fact that they figured out that the Brujah aren't actually all that good at combat despite the fact that the fluff says that they are.
Followers of Set

The Followers of Set, or “Setites” as they are sometimes known, are an Egyptian clan of snake vampires. “Lol Wut?” I hear you say. Well, fuck you. The Setites don't have powers related to the Set Animal, they have powers related to snakes. Because Set is a snake god in fucking Conan the Barbarian. Yes, the Setites are a vampire clan from ancient Egypt where the primary research was done by reading Marvel Comics. That sounds like it should be an exaggeration, but it really isn't. This is Ancient Egypt as explained in a child's book report of some issues of Conan The Barbarian from Marvel Comics. For real.
This actually makes the Setites the least racist of the independent clans, because their background is so poorly researched and ill-informed that it goes out the other side of racism and just becomes pure fantasy. We're talking about Cimmerians and Kothites, not real people. Which makes it a very weird fit for the World of Darkness, which is otherwise set in “Present Day, Present Time.” But we aren't oppressing or insulting any real world groups, so that's a thing. Kind of sad that we have to call that a win, but there you go.
From a discipline standpoint, the Followers of Set get Presence and Obfuscation. That's a cute contradiction and just the fact that they do both is evocative of shady dealer people. They got a persona as corrupters and malfeasants, and it slides in well. All the caveats about how Presence-only feeding works but is not inherently compatible with the Masquerade applies, but this is one of the few discipline sets which actually do what the role says they should do (the others being Toreador, Ventrue, and of course: Tremere). Their signature discipline is Serpentis, which is based primarily on “Shit Thulsa Doom got up to” from a thematic standpoint and “like Protean, only awesome” from an organizational standpoint. Each dot is a variant on the dot you get in Protean, but in general sexed up quite a bit (at least, for the first four dots). So the first dot of Protean gives you funky eyes and the second dot gives you a fight move, the third dot lets you hybernate during the day without catching fire, and the fourth dot gives you an animal form – all broadly the same as Protean except all of them are way better than the Protean versions. Where it gets weird is the last one just lets you rip your heart out and store it in a canopic jar, which is basically useless as opposed to turning into a mist which is pretty fucking cool. Heart-in-a-box is the kind of fire and forget one time ritual that Vampires learn for like one experience point and is a major let down for a discipline capstone. Not that you ultimately cared, because eventually they just said “fuck it” and gave Setites their own thaumaturgy paths and those had capstones that were just fine, thanks.

I think Kaa is literally the reason that Eyes of the Serpent hypnotize people.
Snake vampires are definitely a thing. Some players are going to want to get their Lair of the White Worm on, and while the original Bram Stoker book (yes, that Bram Stoker) is kind of shit, the movie they made out of it is pretty cool. The Setites have potential, their powers actually help them do their shtick and they are altogether one of the clans that fires on the most cylinders. Definitely a faction you'd want to fix rather than purge.
One thing that I should talk about is the problem of evil. Not the Epicurius mic drop on theism, but the fact that the game is about blood drinking vampires. The Setites were unapologetically evil. But all the other factions are also evil, because they are secret societies of man eating monsters. What exactly does it mean that the Setites are “evil?” Different authors had very different ideas, with some being of the opinion that the Setites were ultimate villain material who were trying to destroy the sun like Montgomery Burns, while others were of the opinion that the Setites were basically just as bad as the other factions but were unapologetic about it and had more fun. This kind of moral ambivalence really hurt the ability to do cooperative storytelling. If one book presented the Setites as child molesting sun devouring lunatics and another book presented them as drug dealing hedonists it meant that very plausibly you could have two players sitting at the table with wholly irreconcilable concepts of what is going on and what acceptable actions there might be. White Wolf badly needed to get its head out of its ass and decide how bad its various flavors of bad guy actually were.
Giovanni

Well, that went to a very weird place.
The Giovanni are a family of Italian mobsters and necromancers. Pretty much everything about them can be derived from that. That and really amazingly gratuitous racism. Basically think of any possible Italian stereotype you can, and throw it in there. They are food-centric sexual deviants who lead a crime family that is structured like a mafia family from a gangster movie. The necromancy is actually about contacting ghosts, but there's a lot of corpse fucking in here. Like, so much corpse fucking.
The inherently racist nature of the Giovanni would be a real problem if Italians faced any real discrimination in the United States anymore. If this came out in the 1970s or any time before that, the Italian American Defense League would have gotten every book with Giovanni in it labeled a work of hate. But these days the Italians are like Scottish people or the Dutch, and you're just allowed to say incredibly racist things about them and no one gives a shit. Racism is always a fairly dickish thing, but being a dick to people who are in the club is “gentle ribbing” while being being a dick to the disadvantaged is participating in systematic oppression. I can't get worked up about the cartoonish racism that defines the Giovanni's Italianness, even though it's basically the same thing as the racist tirades that define the Ravnos (shudder).
Giovanni had Potence, Dominate, and Necromancy. Potence and Dominate are probably the most generic Vampire disciplines, and were probably handed out because the author honestly didn't give a single ratfuck what other disciplines they got besides their magic death sight power. The Lasombra ended up in the same boat, and have the same default secondary disciplines. Necromancy was originally the protected shtick of the Giovanni, but quite rapidly various means of dealing with the world of the dead cropped up in regional sourcebooks elsewhere. Various Necromancy variants and alternate takes proliferated so severely that eventually White Wolf made Necromancy into a path discipline with associated rituals not unlike Thaumaturgy.
Moving forward, mafia clans of vampires are awesome. And necromancy is awesome. And there is absolutely no reason for this clan to exist. Mafias of vampires are better when they are multi-clan and White Wolf has established that they are completely incapable of making death magic in any way proprietary.
Ravnos

The Gangrel were originally intended to have Gypsy connections.
To the point that in the first set of the card game, the Gypsies are a Gangrel ally card.
This all has to do with the fact that in Bram Stoker's book called Dracula, Dracula pulls some strings with Gypsies to help him flee across Europe. Dracula had Gypsy allies, so Vampire: the Masquerade wrote up some Gypsy allies for one of the clans (the Gangrel as it happened). And this was of course problematic, because the Gypsy segment in Dracula is embarrassing and racist in retrospect. So when V:tM uses that shit pretty much straight, it's no longer embarrassing and racist in retrospect, but just sort of racist in an ongoing and upsetting way. Remember, Bram Stoker wrote Dracula as getting aids from Slovaks and Gypsies because Bram Stoker was racist against Slavs and Gypsies. Because it was Victorian England, and people were just racist sometimes.
Now the Gangrel are not actually well designed. As I complained about earlier, they don't do the things they are supposed to do. But they fail not only at the things they should do, but also manage to fall flat on the things that were a bad idea in the first place. So the Gangrel Gypsy connection is just sort of tacked on to one side and doesn't make any more sense than the Dracula Gypsy connection did in the source novel. Now the right way to handle that would probably be to quietly sweep that shit under the rug and never speak of it again. Like that stupid idea of turning back into humans at the end of the chronicle by killing your vampire sire. However, what actually happened was that some dumb asshole at White Wolf decided that the problem was that Gangrel just weren't “Gypsy enough” and decided to make a new bloodline that had the “Gypsiness” turned up to 11.

Fucking seriously? Damn it White Wolf!

Fucking seriously? Damn it White Wolf!
Tzimisce

The Tzimisce exist because the Gangrel suck. But unlike the Ravnos, who exist because some fucking White Wolf author said “That's not Gypsy enough! Gypsy Gypsy Gypsy!” the Tzimisce are here because Protean sucks at being a transformation power and the Gangrel don't make terribly convincing Draculas. So in walk the Tzimisce with an aristocratic history as scary Slavic Voivodes and a flatly better transformation power. These guys make better Draculas and they also make better transformation specialists. Their clan disadvantage is even that Dracula thing about having to ship dirt around if they move. But as such things inevitably do, the transformation shtick metastasized and became its own thing... and it went to a pretty weird place.

Wait. What?
So the Tzimisce transformation powers are so much better that they can use them on other people, so they have this weird side-deal going on where they make human centipedes and deadly crab men and shit. Kinda cool, but a serious what-the-fuck. Also totally unplayable in LARP. Also, a kind of subtle point, but these assholes actually don't have mind control powers. In order to command your army of clawed mutant freaks you kinda need to have some kind of ability to do that, and they don't. Tzimisce are definitely one of those factions that really obviously needs more than three disciplines to do their shtick.
Really, transformation needed more than most disciplines to be put on some kind of path schedule where you could be a budget werewolf by taking the Wolf Path and a Conan villain by taking the Serpent Path. And there fucking needed to be an ability to rearrange your own face, because it is fucking ridiculous for there to be transformation magic and have that not be an option. Vicissitude filled a very obvious and very real hole in the rules, but did so in one of the most inelegant ways possible.

This is how the Tzimisce get portrayed, but I have no idea how they are supposed to do that with Vicissitude, Animalism, and Auspex.
The other issue is that these guys were written for the Sabbat, because that is the book that was being written when this clan proposal was on the slush pile. These guys are all aristocratic and have strong ties to the land and shit and these guys are supposed to be one of the main clans of the rebel faction. The brooding domain lords of the East really doesn't fit with the flaming chainsaw wielding revolutionaries that the Sabbat are usually portrayed as. The Sabbat are deeply incoherent, and the Tzimisce don't help clear that shit up.
Lasombra

There isn't much to say about the Lasombra so I won't say much. They are basically Ventrue with a disadvantage that could actually work (they have mirror problems, which is a real problem for the masquerade but something that can be worked with). They swap Fortitude for Potence because they are evil, but that doesn't matter because both disciplines blow. And they have the stupidly named Obtenebration, which is shadow magic. The ability to control shadows makes a token effort at convincing you that it's the evil version of Presence (which was doubtlessly exactly how it was first pitched) by giving you the power to “look awesome” through creative lighting control, but it's mostly about making solid tentacles of shadow to hentai rape people.

Basically, the Lasombra are about what the Ventrue should have been. Pretty much across the board. The Ventrue do their shtick reasonably well if you mind caulk their unworkable clan drawback, and the Lasombra are pretty much the same thing but with a workable drawback and some proprietary sorcery.
Most of the general problems remain of course, but fundamentally we're looking at a clan whose purpose was to rewrite the Ventrue into being better and more playable. A modest goal, since of course the Ventrue are already one of the better and more playable clans, but this clan succeeds at this goal.