I’m drawing a blank at present so open floor!
"Ringing the changes" a little: about a month ago we had a question involving fictional dogs, which folk were invited to identify from the clues. Doing similarly here, with the same number of fictional cats.
1) The pet of a youthful heroine who has adventures among playing cards and chess pieces and numerous other beings.
2) A conjurer and illusionist of genius: one of a number of felines individually celebrated in the same canon.
3) Reckoned "the grand-daddy of them all" cats-wise, in the particular branch of the (using the term broadly) art-form concerned: created 1919, still going strong.
4) One of a pair of incompetent and over-generous business partners: the two are friends, notwithstanding their being of different species between which traditionally and more commonly, an age-old enmity obtains.
5) This cat is taught human speech, and the use of it; which proves not a happy development for any of the humans involved in the episode.
6) A supporting member of the cast: leader of a musical ensemble in a European capital early in the twentieth century.
7) One party in a bizarre love / hate triangle among residents of Coconino County, Arizona. Those concerned, are our cat; a mouse; and a dog: cat unrequitedly loves mouse, mouse hates cat, dog loves cat and therefore persecutes mouse.
8) A former witch's-familiar, who has transferred allegiance to "the side of light": assists the hero in his struggle against his (the hero's) witch-governess and her evil associates.