Merfolk Looter – Magic 2012 common. Merfolk Looter is both the first and the most recent Looter, associating the name with the "draw a card, then discard a card" ability in Exodus, then watching as Cephalid Looter, Artful Looter, and Looter il-Kor ran with it. In both Magic 2010 and Magic 2012 (and also Seventh Edition and Tenth Edition), the original looter has been showing off the idea in the core set.
Fling – Magic 2012 common. Fling entered the core set in Magic 2011, just after Stone Giant left with Magic 2010. Does the core set only have room for one card based around a giant throwing a creature at your opponent?
Deathmark – Magic 2012 uncommon. Have you noticed that the eye in Deathmark is upside-down? The eyebrow is below it. If you could zoom out, you'd probably see a dead body on its back, with the head lolling around. Even creepier!
Mana Leak – Magic 2012 common. Mana Leak first appeared in Stronghold, back in 1998. It didn't make it into the core set until it replaced Counterspell in Eighth Edition. Then neither of them were in Tenth Edition or Magic 2010, but Mana Leak returned for both Magic 2011 and Magic 2012.
Druidic Satchel – Magic 2012 rare. It's fairly obvious that there's a face on the flap of Druidic Satchel, right? But if you look a little more closely, the strip of leather that goes through the buckle appears to be the satchel-face's tongue. That looks uncomfortable!
Garruk, Primal Hunter – Magic 2012 mythic rare. Garruk Wildspeaker is a hunter to the core, a planeswalking predator whose hunting ground is the entire Multiverse. Gripped with a need to test his might and resolve against ever greater challenges, his life's calling has become an endless hunt of the most ferocious and dangerous game that each plane can offer.
Chandra, the Firebrand – Magic 2012 mythic rare. Fearing her as a source of immense and unpredictable power, many authorities have sought to restrict and control Chandra Nalaar. Such attempts come into direct conflict with her need for independence and freedom. Any time Chandra's wild inner fire comes into contact with rules and strictures, the results are sure to be explosive.
Sorin Markov – Magic 2012 mythic rare. Sorin is well-traveled and well-heeled. Having seen hundreds of planes over thousands of years, he has become a sort of bon vivant, seeking diversion and novelty. But despite his fundamentally hedonistic nature, Sorin does feel the pull of more lasting concerns. Over his long life, this tendency has resulted in an arcare schedule of engagements and forays to far-flung planes.
Jace, Memory Adept – Magic 2012 mythic rare. Curiosity has always gotten the better of Jace Beleren. As a magical prodigy, he delved deeper into lessons of sorcery than the other mage academy students and succeeded to the point that even his instructors were suspicious of him. As a specialist in mind magic, Jace uses his abilities to gaze into the minds of others, uncovering their closely guarded secrets.
Gideon Jura – Magic 2012 mythic rare. Unlike most Planeswalkers, Gideon doesn't hesitate to enter combat. He wields a sural, a three-bladed, whiplike weapon that also serves as a focus for his spellcasting. He also practices hieromancy, the magic of holy justice.
Scrambleverse – Magic 2012 rare. From the Magic 2012 FAQ: "Once Scrambleverse starts to resolve, no player may respond until it has finished resolving. For example, you can't wait to see who will control a creature before deciding whether or not to activate one of its abilities."
Grand Abolisher – Magic 2012 rare. From the Magic 2012 FAQ: "Grand Abolisher doesn't stop your opponents from activating abilities of artifact, creature, or enchantment cards in zones other than the battlefield (like cycling abilities, for example)."
Sphinx of Uthuun – Magic 2012 rare. From the Magic 2012 FAQ: "In multiplayer games, you choose an opponent to separate the cards when the ability resolves. This doesn't target that opponent. Because the cards are revealed, all players may see the cards and offer opinions."
Battle Rampart – Mercadian Masques common. When Battle Rampart was printed in Mercadian Masques, it was directly opposed by Rampart Crawler, which specializes in thumbing its nose at walls named "Rampart." It would be a few years until Crude Rampart would be printed in Onslaught with its ability to masquerade as a 2/2 creature lying in wait for the lizard mercenary.
Twilight's Call – Invasion rare. As you can tell from the flavor text, Twilight's Call is set in a Keldon Necropolis. And the art description backs this up, instructing Mark Romanoski to portray "Keldon warlords in black armor crawl[ing] out of their mausoleums, ready for battle." It's a good thing Keldon warlords are entombed in their armor!
Dawnglare Invoker – Rise of the Eldrazi common. As alluded to in the Dawnglare Invoker flavor text, the Kor worshipped gods called Emeria, Ula, and Cosi. It was only after the Eldrazi were loosed upon Zendikar that they discovered they were really Emrakul, Ulamog, and Kozilek.