This was unfortunately leaked already which is the reason Maze’s End spiked so significantly, but it is now official thanks to the Twitch stream design reveal by WotC (live at time of this writing).
I’m writing a Patreon alert to advise you to buy copies of Guild Summit – it is an uncommon from Guilds of Ravnica that can be found for $0.10-0.20 and foils around $3. These are both great pickups as Guild Summit should be a Ravnica-specific themed card and thus feels safe from a reprint. (worst case it is reprinted and you’re out a few bucks at most).
I think without a reprint this will pop to $1-2 and be a fantastic quick flip buylist play.
More coverage coming throughout the day so be sure to stay tuned to our Patreon for all the updates and info!
Chris