It's common for Google to drop a few accessories in the Play Store each time a new Nexus comes out, but they often don't ship until at least a few weeks after the device itself. Maybe by the time you get your hands on a Nexus 6 the newly listed cases (by Case Mate) will be shipping. The folio and clear case for Motorola's first Nexus are in the Play Store, but you can't order yet. Actually, they're both kind of ugly and expensive, so maybe you don't want to.
The folio-style case covers the front of the device and can be used as a stand when you open it up. There are slots for credit cards and the entire thing is clad in leather. The "Naked Tough Case" is a clear plastic shell that adds a kickstand to the back. On second thought, I take back what I said before—these are not "kind of ugly," they are hideous. Seriously, Google. What gives?
Still, Google thinks these are suitable enough for the Nexus 6 that they're selling them in the Play Store. If you want one, the folio is going to be $40 and the Naked Tough Case is listed at $35. We'll let you know when these monstrosities are available, may god help you.