Yesterday a post appeared on the Magic subReddit /r/Magictcg. The original poster has since deleted their account but the image posted contained potential packaging for Amonkhet, Hour of Devastation, and what appears to be the following block of Atlazan and Conquest of Power.

Approximately three hours after the post went live Wizards of the Coast released the following Tweet from the official Magic Twitter account:

Concurrent posts on the Magic Tumblr confirm that these are from a survey on packaging concepts and nothing more.

If the leaked set name is accurate it would represent the first major information dump since the series of unofficial spoilers associated with Oath of the Gatewatch. It would also be the first leak since the move to "Announcement Day" which could take the wind out of the next iteration's sails.

If the characters featured on the packaging are accurate we can expect new editions of Nicol Bolas and Ajani coming in the next year, as well as a potential return of Vraska, the Unseen.

We will update this post if any new information becomes available.

Update: Today's Daily Magic Update contained the following quote:

We make set name announcements on Announcement Day, not in surveys being sent out to the public.