
Courier's Briefcase | Artifact | Treasure | When Courier's Briefcase enters, create a 1/1 green and white Citizen creature token.
{T}, Sacrifice Courier's Briefcase: Add one mana of any color.
{W}{U}{B}{R}{G}, {T}, Sacrifice Courier's Briefcase: Draw three cards. | Josu Hernaiz

Counterflux | Instant | | This spell can't be countered.
Counter target spell you don't control.
Overload {1}{U}{U}{R} (You may cast this spell for its overload cost. If you do, change "target" in its text to "each.") | Adrián Rodríguez Pérez

Epic Experiment | Sorcery | | Exile the top X cards of your library. You may cast instant and sorcery spells with mana value X or less from among them without paying their mana costs. Then put all cards exiled this way that weren't cast into your graveyard. | Dan Murayama Scott

Nivix Cyclops | Creature | Cyclops | Defender
Whenever you cast an instant or sorcery spell, Nivix Cyclops gets +3/+0 until end of turn and can attack this turn as though it didn't have defender. | Wayne Reynolds

Steam Augury | Instant | | Reveal the top five cards of your library and separate them into two piles. An opponent chooses one of those piles. Put that pile into your hand and the other into your graveyard. | Dave Kendall

Stormchaser Mage | Creature | Human Wizard | Flying, haste
Prowess (Whenever you cast a noncreature spell, this creature gets +1/+1 until end of turn.) | Clint Cearley

Frostburn Weird | Creature | Weird | {U/R}: Frostburn Weird gets +1/-1 until end of turn. | Mike Bierek

Keranos, God of Storms | Legendary Enchantment Creature | God | Indestructible
As long as your devotion to blue and red is less than seven, Keranos isn't a creature.
Reveal the first card you draw on each of your turns. Whenever you reveal a land card this way, draw a card. Whenever you reveal a nonland card this way, Keranos deals 3 damage to any target. | Daarken

Turn | Instant | | Until end of turn, target creature loses all abilities and becomes a red Weird with base power and toughness 0/1.
Fuse (You may cast one or both halves of this card from your hand.) | Ryan Barger

Sarkhan Unbroken | Legendary Planeswalker | Sarkhan | +1: Draw a card, then add one mana of any color.
−2: Create a 4/4 red Dragon creature token with flying.
−8: Search your library for any number of Dragon creature cards, put them onto the battlefield, then shuffle. | Aleksi Briclot

Chromanticore | Enchantment Creature | Manticore | Bestow {2}{W}{U}{B}{R}{G} (If you cast this card for its bestow cost, it's an Aura spell with enchant creature. It becomes a creature again if it's not attached to a creature.)
Flying, first strike, vigilance, trample, lifelink
Enchanted creature gets +4/+4 and has flying, first strike, vigilance, trample, and lifelink. | Min Yum

Izzet Guildgate | Land | Gate | This land enters tapped.
{T}: Add {U} or {R}. | Kirsten Zirngibl

Wandering Fumarole | Land | | Wandering Fumarole enters tapped.
{T}: Add {U} or {R}.
{2}{U}{R}: Until end of turn, Wandering Fumarole becomes a 1/4 blue and red Elemental creature with "{0}: Switch this creature's power and toughness until end of turn." It's still a land. | Florian de Gesincourt