One of these (only interested if NS is tradable):
BETA:
2x DOTA Tradable Gift
GIFTS:
Alan Wake Franchise (Alan Wake CE + American Nightmare)
Alice Madness Returns
Awesomenauts
Counter Strike Global Offensive
Dead Space 1
Dead Space 2
Divinity 2 Dragon Knight Saga (includes both Classic and Director's Cut)
Dungeon Defenders
Evil Genius
Fallout 3 GOTY
Homefront (+3 DLC available)
Iron Brigade
Just Cause 2
Killing Floor Bunlde (with all current DLC)
Left 4 Dead 2
Magic the Gathering 2013
Men of War Assault Squad GOTY
Metro 2033
Nation Red
Nexuiz
Nuclear Dawn
Portal 2
Risen
Rock of Ages
Rome Total War Complete (includes Alexander)
Spore Creepy and Cute Pack
Starvoid
Star Wars Knights of the Old Republic
Star Wars Knights of the Old Republic 2
Terraria
Tomb Raider Anniversary
Tomb Raider Legend
The Club
The Witcher Enhanced Edition
The Ship Complete 2-pack (gives an extra gift copy on activation)
Titan's Quest Gold (2 games)
Torchlight
Trine 1+2 Franchise
Two Worlds 2 Velvet Edition
Wargame European Escalation
Warhammer 40K Dawn of War Platinum (3 games)
STEAM KEYS:
Avadon the Black Fortress
Cogs
Cortex Command
Crayon Physics Deluxe
Eufloria
Fantasy Wars
Hitman Blood Money
Insecticide Ep. 1
Lead & Gold
Majesty 2
Men of War
Metro 2033
Might & Magic Clash of Heroes
Might & Magic Clash of Heroes I am the Boss DLC
Reign: Confict of Nations
Rig n' Roll
Robin Hood
RUSE DLC 2
RUSE DLC 3
Shoot Many Robots
Space Rangers (this game is no longer in Steam store)
S.T.A.L.K.E.R.: Shadow of Chernobyl
Stellar impact
Superbrothers Sword & Sworcery EP
Supreme Commander 2
Swords & Soldiers HD
The Last Remnant
Theater of War 2: Africa 1943
Velvet Assassin
Warhammer 40,000: Space Marine
Zen Bound 2
HIB3 Android 3 Bonus key (World of Goo, Anomaly, Osmos, EDGE)
HIB6 Gift Link (Vessel, Torchlight, Rochard, SPAZ, Shatter, Wizorb, BIT.TRIP.RUNNER, Gratuitous Space Battles, Jamestown)
HIB Android 4 Gift Link (Eufloria, Crayon Physics Dlx, Avadon, Cogs, Splice, Swords&Soldiers HD, Zen Bound, Superbrothers EP, Walking Mars, Canabalt)
NON-STEAM KEYS:
Omegalodon Desura key
Zombies! Desura key
CoH: Tales of Valor (works with Steam if you already have another CoH game to use the key with or off-Steam standalone)
ARMA 2 (not CO)
MISC:
Impreial Tricorne (SK item)
Medieval War Helm (SK item)
Golden Laurel (SK item)
Genuine Foppish Physician (TF2 item)
Genuine Distinguished Rogue (TF2 item)
Genuine King of Scotland Cape (TF2 item)
Genuine K-9 Mane (TF2 item)
Genuine Stovepipe Sniper Shako (TF2 item)
Genuine Vigilant Pin (TF2 item)
Genuine Crafty Hair (TF2 item)
Genuine Area 451 (TF2 item)
Steam Community Access Beta (tradable)
Transcripted Level Demo (Steam key)
Airmech Beta + 1000 Diamonds (key)
Firefall Beta (key)
SMITE Beta (key)