Pet cats, dogs, toads, goats, and even beetles have long been involved in folk magical practices of witches.
Ruth Marshman in the 1850’s for example, called herself a witch, and she kept toads in her home.
In the 1520’s Elizabeth Francis inherited a cat named Sathan from her mother and the cat gave her advice (often bad advice) and helped her do killing curses. The cat got to expensive to feed so she prayed to god and the cat was changed to a toad, which was presumably much cheaper to feed.
Witches traditionally are thought to have fed their familiars some of their own blood from their witches tit (a third nipple or a mole). That doesn’t seem wise, we don’t want our cats and dogs getting a taste for blood, they might start biting and get forced to be put down! But one can work with a willing pet to exchange energy and bond with them.