"Despite their bravado, mortals are fragile

Labs Abandoned Air Temple Abandoned Campground Abandoned Outpost Abraded Bluffs Abstergo Entertainment Abundant Countryside Academy Ruins Access Tunnel Accursed Duneyard Adagia, Windswept Bastion Adanto, the First Fort Adarkar Wastes Adventurer's Inn Adventurers' Guildhouse Aether Hub Agadeem, the Undercrypt Age-Graced Chapel Agna Qel'a Airship Engine Room Akoum Refuge Akoum Teeth Alchemist's Refuge Ally Encampment Alpine Meadow Amonkhet Raceway An-Havva Township Ancient Amphitheater Ancient Den Ancient Spring Ancient Tomb Ancient Ziggurat Animal Sanctuary Arcane Lighthouse Arcane Sanctum Arch of Orazca Archaeological Dig Archway Commons Archway of Innovation Arctic Flats Arctic Treeline Arena Arena of Glory Argoth, Sanctum of Nature Arid Archway Arid Mesa Asgardian Citadel Ash Barrens Atzal, Cave of Eternity Auntie's Hovel Avengers Hangar Avengers Tower Avishkar Raceway Axgard Armory Aysen Abbey Azcanta, the Sunken Ruin Azorius Chancery Azorius Guildgate Ba Sing Se Bad River Badlands Bala Ged Sanctuary Balamb Garden, SeeD Academy Baldur's Gate Balduvian Trading Post Ballroom Bant Panorama Barad-dr Barbarian Ring Barkchannel Pathway Baron, Airship Kingdom Barracks of the Thousand

The addition of new cards lends some hope to those optimistic for a third Planechase product sometime in the future, but this wouldnt be the first time Wizards has trotted out a neglected format for promotional reasons (Im looking at you, Two-headed Giant)
(2016-04-08) You can't sacrifice a Clue to pay multiple costs
This includes token-makers like Gelatinous Genesis or mass reanimation like Rise of the Dark Realms
AMPHIBIAN DOWNPOUR The final blue card on the list today is Amphibian Downpour