Cowardly Lion: Stan never gets over his instinctive fear of any and all potential and real threats but if Zev/Xev is in real danger he will always at least try to help her. The first evidence of this is as soon as "Supernova" when he refuses and even punches Giggerota when she tries to get him to abandon Zev and Kai on the doomed Brunnis and escape with her on the Lexx.
Beware the Nice Ones: She may be one of the nicest, most moral and compassionate people in either universe but she's also part Cluster Lizard and will not hesitate to hand you your ass if you get her genuinely mad.
Half-Human Hybrid: She was turned into one of these when her love slave transformation process went wrong. Her other half comes from Cluster Lizard DNA.
Heroic Sacrifice: In "Terminal", in order to save Kai. She is resurrected in the next episode, however.
Howl of Sorrow: She lets out one of these (combined with a Cluster Lizard screech) when Kai "dies" in "Giga Shadow".
Idiot Ball: She keeps a firm grip on this as she's pretty much the one responsible for getting the crew into almost every situation for the show's entire run; disregarding perfectly good advice, walking into dangerous situations and ignoring signs that things aren't right are standard for her. Partially justified due to her upbringing as she's not familiar with normal behaviour and is desperate for new experiences and adventure.
I'm a Humanitarian: In "Terminal", after being tortured nearly to death, she transforms from her normal human form into that of a Cluster Lizard, before proceeding to devour her captors. Also in Season 4 when she enters her mating cycle.
Shower Scene: Several, with the first one being especially loaded with fanservice.
Sleeps with Everyone but You: Absolutely refuses to have sex with Stan, although she does come close on one occasion due to desperation. There was also that one time they were gender-swapped.
Vitriolic Best Buds: Eventually reaches this with Stan. She's the first to insult him and point out his shortcomings but she'll also be the first to leap to his defense. She even once killed what she'd believed to be a living version of Kai because he attacked Stan.
Took a Level in Jerkass: Following his reset that causes him to imprint on Kai instead of Xev, 790 gets far more homicidal. Kai even rejects an idea to reset him back to Xev, even though it's a simple fact that he was never so aggressive when in love with her.
He did also take serious damage to his limited brain tissue at a few points which helped make him progressively less clever and helpful.
Living Ship: And very living, most metal and control bits are clearly installed later. And the ship's living nature means it needs to eat.
Planet Eater: The Lexx feeds itself by stripping organic material from planets; in "Eating Pattern," when it lands on a planet where the surface is mostly barren, it seems to sift through the dirt for nutrients buried within; while in "Dutch Treat," it flies low over the surface and sucks up the more obvious nutrients (trees, grass, animals, the population of Holland) like a vacuum cleaner. On a few occasions, the Lexx will eat bits of planets it blows up, but doesn't get very much out of it since it's "just a snack".
Boomerang Bigot: He has a strong desire to exterminate all human life, in spite of the fact that he himself was fully human until he merged with the Insect essence, which is the cause of his desire to Kill All Humans.
Creepy Monotone: On a few occasions, he'll start talking in a very low, creepy, emotionless manner
Cyborg: By the time the crew of the Lexx meet him, the only organic parts of him left are his head and a few of his internal organs.
Man in the Machine: As previously mentioned, the only organic parts of him left are his head (attached to a floating jar) and some of his organs (contained and preserved in said floating jar), and he uses mechanical drone arms to do everything. Later, when his jar is destroyed, his head is transported to the inside of a four-legged Humongous Mecha instead.
There Is No Kill Like Overkill: When he promises to save the crew of the Lexx for last, he's not kidding; he waits until he's converted the entire universe into Mantrid Drones, then chases them with those drones. All of them.
Would Hurt a Child: He uses his drone arms to create the illusion of a space station made of candy to entice Norb into getting within his reach, before using the drones to chase after the poor kid and kill him, before using more drones to impersonate him.
Resurrective Immortality: He can return after being killed, once a certain time period had elapsed. Worse, he can choose where he will reappear, and what his appearance will be, making him a de facto shapeshifter.
Ambiguously Human: She looks human, and technically wouldn't be a "cannibal" otherwise, but her long, prehensile tongue and superhuman physiology (she's incredibly strong and capable of surviving a fall of what looked like several hundred meters) make her species ambiguous. No other similar entity appears in the series. Well, other than the several dozen other cannibal women, but they're not connected either.
Extreme Omnivore: She will eat just about anything that can be classified as "organic". Including bits of the Lexx.
Karmic Death: First she gets abandoned on a planet with the sun about to go nova because she kept ripping pieces off her moth to eat and telling it to shut up when it protested and then ends up being eaten when she reincarnates on Earth after getting a carnivorous plant excited about eating people.
Blue and Orange Morality: A predator to the core, she eats people without any moral qualms at all, and Kai, in season 4, sees no reason to stop "Lyekka's twin sister Lyekka" from eating a chunk of the planet.
Planet of Steves: There are a couple of Lyekkas - "Lyekka" the nicer one in Season 2, "Lyekka," created by the Gardeners on Water in Season 3, and "Lyekka's twin sister Lyekka," the antagonist from season 4. Every Lyekka is named Lyekka, and uses the same form, the girl from Stanley's dreams.
Voluntary Shapeshifting: For most of her on-screen time she takes the form of a girl Stanley once had a crush on, having learned of the girl's name and appearance from his dreams. She also tends to shift into outfits that feature in Stanley's dreams, too (which, given that this is Stan we're talking about, are rather tight and quite revealing outfits).
Warm Bloodbags Are Everywhere: She is very matter-of-fact about this: she'd "prefer" not to eat her human friends, but deprived of other food sources, she would.