This post will talk about animals that posses magickal abilities. I shall start by only speaking on the cat. If you have any new information, please feel free to post it at any time, enjoy.
There are two types:
The Witch's cat
The Pride cat
First, we shall discuss the witch's cat. It is a cat that possess the ability to perform small magickal feats. The term "Witch's cat" refers to a type nomenclature, not a specifically owned being, that is: a Witch's cat could be owned by anyone, not just a "witch." These cats may be partially responsible for why cats have a reputation of having "nine lives." If you have a Witch's cat, you will know by its constant curiousness and desire to be around you as you perform spells and/or rituals. In order to begin teaching a Witch's cat spells, you need to astral project with your cat and go find a Wood Elf and manage to convince it that your cat deserves to learn a certain spell, or series of spells. Cats are masters of going to the astral planes, that should be the least of your concerns. Send a telepathic message to your cat, requesting for it to go with you (if you wonder how to do this, it is simply like sending a telekinetic message to a human, if you do not know how to do this, then look it up on this site, or Google it.), hopefully they will accept. Once you return from the astral, train with your cat in these spells it learned. Now remember, your cat will never, even in advanced stages, be able to perform large magickal feats, just small useful ones.
The Pride cat is particular to Wiccans, it is simply a cat that can change into a lion. You need to have very deep ties with Wicca and the spirit world or very good luck to be able to obtain one. These cats cannot perform magick, they can only transform but are fiercely loyal companions.