Actually, there aren't a ton of cat goddesses in Egyptian mythology; what there are are a ton of feline goddesses, with the overwhelming majority appearing as lionesses. Ra, the sun god who was for large stretches of Egyptian religion the most important deity, was believed to be protected and supported by his daughters, who were each in turn given the title of the Eye of Ra and who were almost all lioness-headed. Symbolically, the lioness represented the power to destroy Ra's enemies and defend him from all dangers, just as lionesses performed all the hunting and defense for their prides, so it followed that goddesses who took that form would be the most dangerous and formidable of all deities.
The two most famous Eyes of Ra are Sekhmet, the rampaging blood-drinker who had to be calmed to keep her from destroying all life in the world, and Bast, the cat-headed goddess of the moon and protector of the pharaoh, but you specifically asked about less well-known felines, and we aim to please. Possibly the first among the other Eyes is Tefnut, the primordial goddess of moisture; she was created as Ra's daughter along with her brother Shu, the lord of air, and the two of them married and gave birth to the second primordial pair of Nut and Geb, gods of sky and earth.
Tefnut, however, grew dissatisfied with her situation; she quarreled with Ra and chafed against his control, and eventually disobeyed him completely and transformed into a lioness, running into the wilderness to hide in the southern deserts. Her refusal to return left Ra without a defender, and therefore the god Thoth was dispatched to find her and bring her home, which involved him being forced to transform himself into a baboon and wander the wilderness for years himself before he was able to locate her and persuade her to come back. Tefnut did eventually return, but she did not take up her mantle again; she retired to become one of the less fierce among the gods, and Ra replaced her with a new Eye to serve him to ensure that Tefnut would never grew restless again.
Tefnut's story is an archetypal one followed by several of the later Eyes of Ra; like Tefnut, they eventually found themselves no longer pleased to be subservient to Ra, and escaped into the desert to assert their defiance, from which they were variously retrieved by Thoth (as in the case of Pakhet, Mestjet and Tefnut herself), their consorts (as in the case of Mekhit, who was recovered by her husband Anhur), or occasionally even Ra himself, who personally found and healed Bastet when she was poisoned on her travels.
It can be difficult for modern viewers to differentiate between the different Eyes of Ra. They share many features in common, the most obvious being the lioness's head and solar disk worn atop it, and since they also share the same archetypal stories of serving, protecting and eventually rebelling against Ra, what they're doing in a given piece of art doesn't always shed a lot of art on the situation. Egyptologists are able to tell the goddesses apart primarily based on small details of their iconography and sometimes the consort they are paired with or the location their images were found; compare below, for example, these three images, one each of Menhit, Pakhet and Mestjet.
The differences are subtle, to say the least, but that's intentional; the Eyes of Ra were supposed to be literally able to step into the same role interchangeably, so it's no wonder they have very similar imagery and behavior.
But this has been all about lions all the time, and the original question was specifically about cats. The most major cat deity is of course Bast, the lady patron of all cats and mother who nurses the pharaoh; she was also originally an Eye of Ra and appeared as a lioness, but slowly transformed into a cat over time, thanks in part to the rise of Sekhmet as the most popular lioness figure in the kingdoms and in part to the increasing popularity of cats as pets during the beginning of the New Kingdom. For a while she was shown interchangeably as a cat or a lion, but by the ninth century B.C.E. she had become almost exclusively a goddess of cats.
Bast in her role as mother cat was often shown in fully zoomorphic form as a cat herself; even when she was shown as an anthropomorphic woman with a cat's head, she was often accompanied by a litter of kittens around her feet, representing her role as mother and the symbolic dependence of both cats and humans upon her as a sacred caregiver. Such was the strength of her role as a mother that she was sometimes equated with Mut, the ancient mother-goddess, and children were often given litters of kittens as gifts in her honor ensure that she would act as mother to both human and animal in the same household.
And zoomorphic Bast brings me to one of our favorite images of Bast: the Cat of Ra.
The Cat of Ra retains Bast's later image as a cat rather than a lion, but in this form she also still draws upon the violent legacy of her origins as the Eye of Ra. The Cat of Ra is almost always depicted killing Apep, the great evil serpent that attempts to devour Ra and the sun each night, in fully animal form while wielding a khopesh and grimacing to display her frightful teeth and power. While the mantle of Eye of Ra has belonged to many lioness goddesses, only Bastet appears as the avenging Cat, destroying Ra's most hated enemy entirely on her own. The question of exactly what is happening in the scenes where the Cat of Ra attacks Apep is up to interpretation as we have few surviving written texts describing the event, but hymns describe the Cat as combining all the best qualities of various other gods into one ferocious package.
The Cat of Ra is most commonly considered to be a form of Bast, but this designation is occasionally in question. Some scholars (mostly older ones who interpreted the Cat as being essentially masculine because of its sword-wielding ferocity) have identified the Cat as instead being a form of Ra himself, fighting Apep directly. Others have suggested that the Cat might not be a cat at all, pointing to its exceptionally long ears in some pieces of ancient art as evidence that it may be intended to be some other creature. What kind of creature is up for debate, although theories include a fanged rabbit, a desert jackal or a symbolic beast not actually found in nature, similar to the strange composite creature associated with Set.
But Bast is the most likely candidate, and given her history as one of Ra's chosen warriors, it's not surprising that she might continue to destroy his enemies even as she gently nurses the pharaoh along with her many litters of kittens. For the ancient Egyptians, felines were the most powerful of defenders and most dangerous of foes, and that applies whether they're musclebound wilderness monsters or dainty household pets.