It's the key from GMG ( http://www.greenmangaming.com/s/ro/en/pc/games/action/spec-ops-the-line/ )? If so, I can offer Dead space 1+Magicka tradables.
One of the below keys:
AMAZON AND UBI KEYS:
Hitman Blood Money
Metro 2033
Might & Magic Clash of Heroes
RUSE DLC 2
RUSE DLC 3
Shoot Many Robots
Supreme Commander 2
S.T.A.L.K.E.R.: Shadow of Chernobyl
OTHER KEYS:
Avadon the Black Fortress
Cogs
Cortex Command
Crayon Physics Deluxe
Eufloria
Fantasy Wars
Insecticide Ep. 1
Lead & Gold
Majesty 2
Men of War
Reign: Confict of Nations
Rig n' Roll
Robin Hood
Space Rangers (this game is no longer in Steam store)
Stellar impact
Superbrothers Sword & Sworcery EP
Swords & Soldiers HD
The Void
Theater of War 2: Africa 1943
Velvet Assassin
Zen Bound 2
HIB3 Android 3 Bonus key (World of Goo, Anomaly, Osmos, EDGE)
red orchestra 2 goty gifts
medieval 2 complete. gifts
red faction Armagedon gifts
rome total war gold gifts
prototype key.
rogue warrior key
Alan Wake American Nightmare key
for spec ops
Anything here http://www.steamtrades.com/trade/8htvG/h-darkness-ii-awesomenauts-homefront-stalker-soc-red-faction-arma-guer-w-offers
For Spec Ops The line?
Maybe My Fear 3 or BioShock 1 + Tomb Raider: Anniversary or Mirror's Edge + BioShock 1 (all games are tradeable) for your Spec Ops: The Line?