A Puppie, that you need to feed and play with (all optional!) that always awaits you in your virtual home - that would be incredible and could also lead you to emotionaly bind your customers to the oculus eco system.
If someone doesn't want to look for his pet - allow a robot drone, that cares for itself.
But even if your pet would just run around and chill in your home - this would be a beginning and would add life to your home.
I absolutely want robot animals, cats, all the animals. Give me animals!! Especially if the animals have varied AI and can interact with stuff, like sometimes you'll go to Home and they'll be sleeping on the couch, sometimes they'll come up to you and interact, maybe they sleep by the fireplace or watch things that move, I like this plan.
Way in the future, but give every object the possibility to be custom programmed with AI. A chair that follows us around, or an imported .obj that stops moving every time we look in its direction.
The existing faerie is a brilliant start and my favourite item so far, you could start with tweaking it's already good iterations as oposed to starting from scratch.