List of Steam Games with Multi Packs.

With Giftable copies on Purchase.

• The Ship Get two giftable activations with your game.
• Frozen Synapse Get a giftable copy with your game.
• Achron Get a giftable copy with your game.

Two Pack's

• Portal 2 Two pack.
• Cubemen Two pack.
• Dead Horde Two Pack

Three Pack's

• Post Apocalyptic Mayhem Three Pack

Four Pack's 

• Terraria Four pack
• Left 4 dead Four Pack
• Magicka Four pack
• Sanctum Four pack
• Payday The Heist Four pack
• Worms: Reloaded Four pack
• Dungeon Defenders Four pack
• Serious Sam 3 Four pack
• Nexuiz Four pack
• Booster Trooper Four pack
• HOARD Four Pack
• Plain Sight Four Pack
• Steel Storm: Burning Retribution Four Pack
• APOX Four Pack
• Bioshock 2 Four Pack
• Borderlands Four Pack
• Borderlands GOTY Four Pack
• Darkspore Four Pack
• Dead Island Four Pack
• Detour Four Pack
• Dino D-Day Four Pack
• Dogfighter Four Pack
• E.Y.E.: Divine Cybermancy Four Pack
• Hoard Four Pack
• Iron Grip: Warlord Four Pack
• Lead and Gold: Gangs of the Wild West Four Pack
• Left 4 Dead Four Pack
• Nation Red Four Pack
• Nuclear Dawn Four Pack
• ProtoGalaxy Four Pack
• Renegade Ops Four Pack
• Serious Sam HD: The First Encounter Four Pack
• Serious Sam HD: The Second Encounter Four Pack
• Shattered Horizon "Clan Pack" Four games for price of three
• Sol Survivor Four Pack
• The Scourge Project Four Pack
• Vertex DispenserFour Pack
• Faerie Solitaire Four Pack
• Torchlight Four Pack
• Zero Gear Four Pack
• Shoot Many Robots Four Pack
• Bunch Of Heroes Four Pack
• Street Fighter IV: Arcade Edition Four Pack (Country restriction)
• Section 8:Prejudice Four Packs (Country restriction)

*All games have option to buy single player.