Apart from dragons, cats are the only creatures known to absorb magicalenergy, but no one knows what they do with it. They are also instantly able to recognize witchers and exhibit an obvious disdain for them, hissing at them. Cats can also see through invisibility.
Codringher's cat was the only resident of the agency to survive Schirrú's visit.
The Trappers' path was also crossed by a black cat as they entered the village of Glyswen, causing some of them to comment and make warding signs. As it turned out, they were right to be wary.
There are also werecats, large creatures that are half-human and half feline with powers to bind other similar beasts, such as panthers, to themselves.
In The Witcher 3: Wild Hunt, using the potestaquisitor (quest item) to find magical energy will lead Geralt to a nearby cat, leading to him uttering the lines "ah, there you are" or "damn cat, ffwshhht!".