I only have a cat now. (5-6 years old.) Since my roommate moved in with his bride-to-be. (Who themselves have three big ass turtles and four cats.) But while living with my parents we had over such time...two dogs, multiple parakeets/parrot, a lot of guppies, three turtles, six cats, three injured young squirrels that we nurtured to back to health. (that ignores that dozen or so other cats that came by, that we had in our home at one time for various reasons.) 

[i]They only have one doggo, and three cats now.[/i]([s]and a turtle that they aren't properly taking good care of that I want them to reach out to a pet store already.[/s])

If I had a bigger home and enough money and my cat wouldn't kill it the moment it came across it. I'd totally get a ferret. (maybe a Snek, if I could find ones as chill as the ones we had back at the school I went to, caring for animals.)