Thanks to IGN we have out first proper look at Book 2 Spirits

Korra Book 2 New We get to see some Nick people talk to Mike and Bryan about Book 2, they mention a few things -Spirits can take different forms -Creature Spirits -Light and Dark Spirits

New Spirit We see a short clip, plus some other moments all of which are very spirit focused.

All in all this is definitely a tease ahead of a full on reveal, I doubt we will get more than this this week, but it is a great tease ahead of what I assume will be a big SDCC reveal. Thoughts on the new clips :)