The skinny, slippery, round cornered, black AppleTV remote seems to be designed to be as easily lost as possible. Weeks often go by without finding it, during which we use other streaming devices instead.
The Amazon FireTV remote is quite easy to lose, but I stocked up on spares when it was on sale for $15.
The TiVo remote is not only too big to lose, it has a remote-finder feature where you can induce it to play a tune. Genius.