Soo-katoa in the Trigun series in episodes over a period of about 3 seasons. She derives pleasure from yarn, and shows other signs of being a catgirl, even though she is discreet and tends toward avoiding making waves and generally being the focus of attention.
Minea from Vassalord is an android maid who can transform into a Persian cat. She spends most of her time in her cat form, only transforming when necessary to carry out her duties around the house or to attack someone.
Rose from +Anima, a Cat +Anima; her fingernails turn into claws and she gains catlike speed. She also has two tiger-like stripes on her cheeks and a stripe on her forehead.
Starfire from Teen Titans transforms into a cat in the comics when hit with a ray that causes evolutionary regression, suggesting that her race evolved from cats, or cat-like extraterrestrial creatures; additionally, she becomes a cat in the anime in the episode Bunny Raven.
Uriko from Bloody Roar 2 and subsequent games (not a catgirl in the first game).
Yoruichi Shihouin from Bleach has the ability to transform herself into a black/dark blue cat as a matter of will (ironically, she is often mistaken for a male in this form as a result of her cat form's deep voice).
Ichigo Momomiya from Tokyo Mew Mew transforms in her Mew Mew form, which gives her black cat ears and a black cat tail, and her ears and tail pop up when she gets extremely excited, or is under immense stress. She transforms into a cat when she is kissed.
In The Destroyer book 32, 'Killer Chromosomes' and then again in book 117, 'Deadly Genes', Remo Williams, the destroyer, faces off against a female mastermind who has genetically modified herself with tiger DNA with plans on similarly transmuting the entire human race.
Kagaya-hime from the novel Fudoki by Kij Johnson (a tortoiseshell cat that transforms into a woman and assumes the role of a warrior)
Kami Osbank, a Turkish woman who is secretly a member of a hidden feline humanoid race known as the Pride, who possess tails, retractable claws, heightened senses, strength and agility, and leopard-like tracks of spots running along their limbs and torsos. Their prehensile tails possess cartilage and muscle rather than bone, and thus with practice can retract to the base of the spine and allow the Pride to live hidden among humans (The Pride, by Edie Bingham)
Odd Della-Robbia from Code Lyoko (while not technically a cat/human hybrid, Odd's form on the virtual reality Lyoko includes over-sized 4-fingered paw-like hands and a prehensile tail - he also displays cat-like-reflexes and mannerisms, has called himself 'a giant purple cat' and has been seen to meow)
Rena, or Reena, from Genesis of Aquarion Even though she is not a catgirl in the usual sense, she has cat-like teeth, and the ribbon she wears in her hair resembles cat ears.
SeeU, a Vocaloid, her cat ears/nekomimi are speakers.
Sekhmet (also spelt Sachmet, Sakhet, and Sakhmet; Greek name: Sacmis), The Egyptian goddess of war and protector of the Pharaoh. She was envisioned as a fierce lioness, and in art, was depicted as such, or as a woman with the head of a lioness, dressed in red, the colour of blood.
Taokaka from BlazBlue: Calamity Trigger. She has a real cat tail and is always wearing a large coat that obscures her true face, only exposing red eyes and a row of teeth.