Valve:
Alien Swarm PC July 19, 2010
Counter-Strike Xbox November 18, 2003
Counter-Strike PC November 10, 2000
Counter-Strike 1 Anthology PC September 13, 2005
Counter-Strike Online PC
Counter-Strike Online 2 PC
Counter-Strike: Condition Zero PC March 23, 2004
Counter-Strike: Global Offensive Mac August 21, 2012
Counter-Strike: Global Offensive PC August 21, 2012
Counter-Strike: Global Offensive PS3 August 21, 2012
Counter-Strike: Global Offensive Xbox 360 August 21, 2012
Counter-Strike: Source Mac June 23, 2010
Counter-Strike: Source PC October 7, 2004
Day of Defeat PC May 6, 2003
Day of Defeat: Source PC September 26, 2005
Deathmatch Classic PC Released
Dota 2 Mac July 9, 2013
Dota 2 PC July 9. 2013
Half-Life PC November 19, 1998
Half-Life Mac December 5, 1998
Half-Life Game of the Year Edition PC January 1, 1999
Half-Life 1 Anthology PC September 26, 2005
Half-Life 2 Game of the Year Edition PC September 12, 2005
Half-Life 2 Collector's Edition PC November 16, 2004
Half-Life 2 Xbox November 15, 2005
Half-Life 2 PC November 16, 2004
Half-Life 2 Mac May 26, 2010
Half-Life 2 Holiday 2006 Collection PC October 24, 2007
Half-Life 2 Survivor Arcade TBA
Half-Life 2: Black BoxPC Cancelled
Half-Life 2: Deathmatch PC October 30, 2006
Half-Life 2: Deathmatch Source PC Released
Half-Life 2: Episode One Mac May 26, 2010
Half-Life 2: Episode One PC June 1, 2006
Half-Life 2: Episode Pack PC April 8, 2008
Half-Life 2: Episode Three PC TBA
Half-Life 2: Episode Three [rumored] PS3 TBA
Half-Life 2: Episode Three [rumored] Xbox 360 TBA
Half-Life 2: Episode Two Mac May 26, 2010
Half-Life 2: Episode Two PC October 9, 2007
Half-Life 2: Lost CoastPC October 27, 2005
Half-Life 2: Platinum CollectionPC November 8, 2006
Half-Life 3PC TBA
Half-Life Generation Blue Shift EditionPC Released
Half-Life GenerationPC Released
Half-Life: Adrenaline PackPC 1996
Half-Life: Blue Shift: SourcePC TBA
Half-Life: Day One PC November, 1998
Half-Life: Initial Encounter PC Europe only
Half-Life: Opposing Force: Source PC TBA
Half-Life: Platinum Collection PC Released
Half-Life: Platinum Collection Second Edition PC 2002
Half-Life: Source PC November 16, 2004
Left 4 Dead Game of the Year Edition PC May 12, 2009
Left 4 Dead Game of the Year Edition Xbox 360 May 12, 2009
Left 4 Dead Xbox 360 November 17, 2008
Left 4 Dead PC November 17, 2008
Left 4 Dead Game of the Year Edition Mac October 5, 2010
Left 4 Dead -- Crash Course Xbox 360 September 29, 2009
Left 4 Dead -- Crash Course PC September 29, 2009
Left 4 Dead 2 Mac October 5, 2010
Left 4 Dead 2 Xbox 360 November 17, 2009
Left 4 Dead 2 PC November 17, 2009
Left 4 Dead 2 Linux TBA 2012
Left 4 Dead 2: Cold Stream Mac August 3, 2012
Left 4 Dead 2: Cold Stream PC August 3, 2012
Left 4 Dead 2: Cold Stream Xbox 360 August 3, 2012
Left 4 Dead 2: The Passing PC April 22, 2010
Left 4 Dead 2: The Passing Xbox 360 April 22, 2010
Left 4 Dead 2: The Sacrifice PC October 5, 2010
Left 4 Dead 2: The Sacrifice Xbox 360 October 5, 2010
Left 4 Dead: Survivors Arcade Import Only
Left 4 Dead: The Sacrifice PC October 5, 2010
Left 4 Dead: The Sacrifice Xbox 360 October 5, 2010
Portal PC October 9, 2007
Portal Mac May 6, 2010
Portal 2 PC April 19, 2011
Portal 2 Xbox 360 April 19, 2011
Portal 2 Mac April 19, 2011
Portal 2 PS3 April 19, 2011
Portal: Still Alive Xbox 360 October 22, 2008
Ricochet PC Released*
SiN Episodes: Emergence [rumored] PS3 TBA
SiN Episodes: Emergence [rumored] Xbox 360 TBA
Team Fortress 2 Mac June 10, 2010
Team Fortress 2 PC October 9, 2007
Team Fortress Classic PC May 30, 1999
Team Fortress: Source PC Cancelled
The Orange Box PS3 December 14, 2007
The Orange Box Xbox 360 October 9, 2007
The Orange Box PC October 9, 2007
*Possible exception