my first thought when I read this question was a chicken.. it could come to the door, and lay the letters on the mat- just like chickens lay eggs

that, or a mail horse, trotting right up to you so you can take the mail off it's back before it trots away again.

I love this question. thanks for thinking of it

question:
if you could find out one thing about your future, what is it you'd like to find out?