If I could have a wizard pet in real life I am not sure which I would pick. As I think about what it requires to take care of a real pet I think of how each of my favor as in cutest wizard pets would be hard to handle and care for. A meow wing is cute but just imagine how much trouble the cats ability to fly would be. Its hard enough to keep a cat without wings off of shelves and things. Though it might be possible to put some wings on my cat for a costume.
Caring for a unicorn would not be a lot different from a horse. well I might be able to make one of my sister's horses look like a unicorn. Would just have to attach a horn to the horse's nose. That sounds like another fun Halloween decoration idea. However not sure how well these pets would tolerate being decorated.
A pair of arcane helpers. Of all the pets I can think of, they would have the most practical use. I would have said arctic fox for the cute factor alone, but those actually exist, and it wouldnt be too hard to get a parka in their size.
Not trying to be in character or anything, but I think that a Sabertooth pet in real life would be pretty cool; or rather a hybrid thereof (like Frostfang or Forlorn Sabertooth, for instance). Honorable mention goes to the Strange Beast.