Good archive of a lot of S2 faces?

There is the Gear app you'll need on your phone anyways. The store in it has a LOT of nice free ones, as well as a massive selection of even nicer paid ones. The store also runs specials every few weeks where you can get nice ones for free.
 
Ah, ok. I used gearfaces.com for my Gear S, but there's very little for the S2 on that site.
 
In addition, you can download Samsung's Gear Watchface Designer and roll your own!