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.
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.
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.