Are you sure you’d want that? The OP said the pet would be tame and well behaved. Lindsay would hardly be herself, then.
Yes, but can it fly?
My other choices would be an octopus (with a very large tank so he’d be happy)
A hyena (again, home defense and fun stares when I walk him. And the reaction of people to his laugh.
Fantasy beasts: A cute lil Beholder or baby Tiamat-type dragon from the D&D cartoon way back when.
A cheetah.
And they have been widely tamed in the past. The… Mongols, was it? Some people, anyway, used them as hunting cats.
Also, squirrels. I mean, they’re just big rodents, right? Same sort of thing as a hamster, just needs a bigger cage?
And a fox. I want. A. Fox.
I totally want an ocelot. I’ve wanted one since I was a very small child.
A larger cat would be nice too: cougar, snow leopard, white tiger…but even if they were totally tame, they’d cost a fortune to feed and I don’t even want to think about litter boxes!
Realistically, definitely an ocelot.
Apparently they’re even cooler if you get a baby squirrel with a foster momma cat.
Sea Lion definitely. Arf! arf! arf!
I’d Like a Ground Pangolin, and if we can engineer some preserved tissue- a Wooly Rhino. Now Someone find me a saddle.
I want a pygmy marmoset. I like monkeys, and they’re the cutest little monkeys I’ve ever seen.
I had a regular marmoset, the ones with the white tufts behind the ears. I rescued it from some people who kept it in a rabbit cage. This thing was the devil’s spawn.
You took my answer! Although any species of pangolin would work for me. I think that ones in the “unrealistic” pile.
I’d also want an ocelot. The dog would wonder why we have a new cat who is bigger than him.
Realistically (unless I ever go back to California, land of no-pets), I would want a bearded dragon and some sugar gliders.
If I were rich enough to provide a proper habitat, I would have a sea otter. They are adorable.
Top choice- a tiger. A male Siberian tiger to be exact. I would name him Kahja. 
Several meerkats. Too damned cute for words.
A skunk. I have always wanted a skunk.
This.
Although, if it really is tamed, do I still need to descent it?
Well, if we’re talking a real animal I’d love a serval.
If imaginary then it’s got to be an Alaspinian minidragon.
I have seen the bird but never knew it’s name until I looked up on wikipedia what a cassowary looks like.
I always thought chinchillas were plants.
Two new things I’ve learned today. Thanks!
For my pet, ever since I saw the movie’s end credits, I’ve always wanted an Experiment 626 as a pet. They’re furry-cute, smart, strong enough to defend you from muggers and incoming laser blasts AND (this is what really made me want them as pets) they cook and do your laundry. 
I’d like a margay, please. This is a housecat sized spotted wildcat.
For an imaginary pet, I’d like a beholder, as long as it likes or loves me. A beholder is usually extremely nasty tempered. It would be both friend and guard to me…
It was the Ancient Egyptians.
I used to have a friend that had a descented skunk named Pumpkin, very friendly, just like an odd cat. The fur isn’t actually soft like a cat, it has those thick sort of guard hairs in the coat and it still has a little residual skunk smell overall, I think it is in the sweat glands oils as well as the scent glands that get removed. They are easy to litter box train.
I would like a caracal, another wolf hybrid that was a high % wolf as Lugh was, and a treecat as a companion not pet, even though they were considered pets through most of the Honor Harrington books. The wolf hybrid and the caracal would have to get along though…
Mogwai,
That giant flying bird thingy in Avatar.
The giant in SW: “The Empire Strikes Back” You know the one where the Millenium Falcon flies up it’s ass and out its mouth in that asteroid field?