Here's a better look at his card:

As you can see, we are crediting each of these designers on the Magic 2015 printing of their card right in the text box!
Who else helped us? Here are a few in their own words on Twitter:
It's official: I designed a Magic card that will be in the M15 set this summer! (I can't show it until June though.) http://t.co/unKzTY4YfX
— Stone Librande (@StoneLibrande) April 13, 2014
Stone Librande is a lead designer at Riot Games, designer of Diablo 3, creative director of SimCity
OH! And this is out now too. Uh. I designed a Magic card in M15. For real. COMMENCE FREAK OUT http://t.co/tya4p6t2d3
— Mikey Neumann (@mikeyface) April 13, 2014
Mike Neumann works at Gearbox Software and worked on Borderlands
its a HUGE honor to announce that i got to design a MTG card in the M15 set along side George Fan, @notch, Brian Fargo, Garriot & many more
— Edmund McMillen (@EdmundMcMillenn) April 12, 2014
Edmund McMillen was the Indie developer behind Super Meat Boy.
You guys I got to design a Magic card with @shawnmain from Wizards of the Coast! It'll be out in this summer's M15 core set! :D! #bucketlist
— Brad Muir (@MrMooEar) April 12, 2014
And Brad Muir works at Double Fine Productions on games like Massive Chalice and Iron Brigade.
So, for completion's sake here is the full list:
- George Fan: designer of Plants vs Zombies
- Mike Krahulik and Jerry Holkins: Gabe and Tycho, creators of Penny Arcade
- Markus Persson: "Notch," creator of Minecraft and founder of Mojang
- Richard Garriot: "Lord British," creator of the Ultima series
- David Sirlin: designer on Super Street Figher II Turbo HD Remix, Yomi
- Rob Pardo: chief creative officer at Blizzard, lead designer of World of Warcraft
- Isaiah Cartwright: lead game designer for Guild Wars 2
- Justin Gary: designer of Ascension: Chronicle of the Godslayer and Solforge
- Stone Librande: lead designer at Riot Games, designer of Diablo 3, creative director of SimCity
- Brian Fargo: founder and CEO of inXile Entertainment, director of Bard’s Tale, Wasteland, executive producer of Fallout
- Mike Neumann: Gearbox Software, creative director on Borderlands
- James Ernest: owner and lead designer for Cheapass Games, designer of Kill Doctor Lucky
- Edmund McMillen: indie designer of Super Meat Boy, featured in Indie Game: The Movie
- Brad Muir: game designer at Double Fine Productions leading Massive Chalice, project lead on Iron Brigade
Wait! There's one missing! You guys!

Magic is a unique game which, in many ways, makes everyone who plays it the designer of their own game. Since Magic is the greatest strategy trading card game on the planet... Ipso facto... you are all awesome game designers!