Cat
Cats is ambiguous between meaning feline animals in general or the domestic house cat. Either is suitable as a source of roguelike encounters.
In a game that uses pets, a house cat would be a typical starting pet.
Wild cats such as lions, tigers, leopards, cheetahs, panthers, lynxes, bobcats, etc. are fairly common roguelike monsters. These animals tend to be quick predators with a combination of biting and clawing attacks.
The house cat should not be ignored, however. While a modest encounter in terms of combat threat, the cat is associated with magic use and could be given some special game abilities as a familiar. They might be given the ability to see invisible characters (an ability their larger cousins might also be given).
ASCII
Usually, roguelike cats comes as c of different colors. Bigger ones can grow to upper case (C), beware!