Avatar: The Last Airbender-esque Freeform RP
Very interested. I'm probably unimaginative but I don't know where a post-Korra adventure would go, although I must admit it could be easily set in the time after she walks through the portal, since the avatar has effectively left the world to itself while she is on holiday. Or alternatively, it could be set in the period when she was in recuperation.
Post-aang and the founding of republic city may also work, but we would have to ignore the comics. Also, everything Briel suggested.