Pet summoning

I would love to see the ability to summon pets. It's really annoying sometimes to go adventuring just to find that you sat down your wolf/cat/parrot in the middle of the woods far from home, or to realize that your already saddled horse wandered off to who-knows-where when you left the gate open.

It would also be cool to see pets that can be shared among multiple players in multiplayer worlds, but this was more of an afterthought.