Okay, I already posted this here, but to keep the list updated, I'm going to go ahead and create this new topic instead.
These are the games that Activison currently control. This is not an official list, and I am probably wrong on a lot of accounts, but this is the closest I've been able to get to a realistic list. Please reply if you find some mistakes, or have additional info.
I've removed a lot of the newer (licensed) games and checked up on which titles would be realistic for Activision to control.
Also, I saw no need to keep the titles already on gog.com AND I added the games made and owned by Sierra and several other companies now owned by, or merged into Activision.
I have made games with more than a hundred votes on the most wanted list bold and those with more than 250 votes bold and underlined. (Yes, I do this kindda stuff for fun)
Also I compiled a quick most wanted list that looks like this. The titles in bold is the titles currently on gog.com, and the numbers are votes on the most wanted list here.
Most wanted Activision games:
1334 - Arcanum: Of Steamworks and Magick Obscura
712 - The Beast Within: A Gabriel Knight Mystery
704 - Vampire: The Masquerade Bloodlines
657 - No One Lives Forever 2
613 - Gabriel Knight: Sins of the Fathers
608 - No One Lives Forever
514 - Diablo: Hellfire
511 - Vampire the Masquerade: Redemption
508 - Gabriel Knight 3: Blood of the Sacred, Blood of the Damned
482 - King's Quest Collection
431 - Space Quest Collection
374 - Interstate '76 Arsenal
370 - Battlezone
366 - Quest for Glory Anthology
362 - Roberta Williams' Phantasmagoria
343 - King's Quest: Quest for the Crown
341 - King's Quest II: Romancing the Throne
338 - King's Quest VII: The Princeless Bride
334 - King's Quest III: To Heir is Human
329 - Battlezone II: Combat Commander
322 - [b}Betrayal at Krondor
321 - Space Quest III
319 - Leisure Suit Larry 7: Love for Sail!
317 - Space Quest II
316 - Police Quest Collection
308 - Space Quest
304 - Phantasmagoria: A Puzzle of Flesh
...
209 - Return to Krondor
154 - Call to Power II
109 - Empire Earth II
And here begins the list of game licenses I suspect Activision controls.
#
3-D Ultra Series
A
* Acropolis (2001) Windows
* Activision Game Vault: Volume 1 (1997) Windows
* Activision Game Vault: Volume 2 (1997) Windows
* Activision Game Vault: Volume 3 (1997) Windows
* Activision's Atari 2600 Action Pack (1995) Windows
* Activision's Atari 2600 Action Pack 2 (1995) Macintosh, Windows
* Activision's Atari 2600 Action Pack 3 (1995) Windows
* Activision's Commodore 64 15 Pack (1995) Windows
* The Adventure Collection (1995) DOS, Macintosh, Windows
* A.G.E. (1991) Amiga, Atari ST, DOS
* Air Bucks (1992) Amiga, Atari ST, DOS
* Alcatraz: Prison Escape (2001) Microsoft Windows
* Asteroids (1998) Game Boy Color, PlayStation, Windows
B
* Bargon Attack (1992) Amiga, Atari ST, DOS
* Battlezone (1998) Windows - 370 votes
* Battlezone: Gold Pack (1999) Windows - 170 votes
* Battlezone II: Combat Commander (1999) Windows - 329 votes
* Best of Sierra Series
* Betrayal in Antara (1997) Windows - 150 votes
* The Bizzare Adventures of Woodruff and the Schnibble (1995) Windows
* Blast Chamber (1996) DOS, PlayStation, Saturn
* Borrowed Time (1985) Amiga, Apple II, Atari ST, Commodore 64, Macintosh, PC Booter
C
* Cabela License Games (http://www.mobygames.com/game-group/cabela-licensees)
* Caesar (1992) Amiga, Atari ST, DOS, Macintosh - 105 votes
* Caesar (Platinum) (1999) Windows
* Caesar II (1995) DOS, Macintosh, Windows - 146 votes
* Call of Duty (2004) J2ME, Windows - 177 votes
* Call of Duty 2 (2005) J2ME, Macintosh, Windows, Xbox 360 - 136 votes
* Call of Duty: United Offensive (2004) Windows
* Castle of Dr. Brain (1991) Amiga, DOS, Macintosh
* Championship Baseball (1986) Amiga, Apple II, Atari ST, Commodore 64, DOS, ZX Spectrum
* The Chronicles of Riddick: Escape from Butcher Bay (2004) Windows, Xbox - 270 votes
* Civilization: Call to Power (1999) Linux, Macintosh, Windows - 150 votes
* Classic Text Adventure Masterpieces of Infocom (1996) DOS, Macintosh
* Cleopatra: Queen of the Nile (2000) Windows - 109 votes
* The Colonel's Bequest (1989) Amiga, Atari ST, DOS
* The Comedy Collection (1995) DOS, Macintosh
* Contract J.A.C.K. (2003) Windows - 288 votes
* Conquests of the Longbow: The Legend of Robin Hood (1991) Amiga, DOS
* CyberStorm 2. Corporate Wars (1998)
D
* The Dagger of Amon Ra (1992) DOS, Windows
* Dark Reign 2 (2000) Windows - 130 votes
* Dark Reign: Rise of the Shadowhand (1998) Windows - 135 votes
* Dark Reign: The Future of War (1997) Windows - 176 votes
* Deathtrack (1989) DOS
* Detroit (1993) Amiga, DOS
* Diablo: Hellfire (1997) Windows - 514 votes
* Die Hard (1989) Commodore 64, DOS
E
* Earthsiege 2 (1996) Windows - 151 votes
* EcoQuest: The Search for Cetus (1991) DOS
* EcoQuest 2: Lost Secret of of the Rainforest (1993) DOS, Windows
* Empires: Dawn of the Modern World (2003) Windows
* Enclave (2003) Windows, Xbox
F
* F-14 Tomcat (1988) Commodore 64, DOS
* The Fantasy Collection (1995) DOS, Macintosh
* Freddy Pharkas: Frontier Pharmacist (1993) DOS, Macintosh, Windows - 110 votes
G
* Gabriel Knight 3: Blood of the Sacred, Blood of the Damned (1999) Windows - 508 votes
* Galactic Empire (1990) Amiga, Atari ST, DOS
* GBA Championship Basketball: Two-on-Two (1986) Amiga, Amstrad CPC, Atari ST, Commodore 64, DOS, ZX Spectrum
* Ghostbusters II (1989) Amiga, Amstrad CPC, Atari 2600, Atari ST, Commodore 64, DOS, MSX, ZX Spectrum, Game Boy, NES
* Grand Prix Racing (1998) Windows
* GUN (2005) GameCube, PlayStation 2, Windows, Xbox, Xbox 360
H
* Hacker (1985) Amiga, Amstrad CPC, Apple II, Atari 8-bit, Atari ST, Commodore 64, DOS, MSX, ZX Spectrum
* Hacker II: The Doomsday Papers (1986)Amiga, Amstrad CPC, Apple II, Atari ST, Commodore 64, DOS, ZX Spectrum
* Heavy Gear (1997) Windows - 172 votes
* Heavy Gear II (1999) Linux, Windows - 196 votes
* Heretic (1994) DOS, Macintosh - votes 228
* Heretic: Shadows of the Serpent Riders (1996) DOS, Windows - 163 votes
* Heretic II (1998) Amiga, Linux, Macintosh, Windows - 266 votes
* Heretic + Hexen Collection (2007) Windows
* Hexen: Beyond Heretic (1995) DOS, Macintosh, Nintendo 64, PlayStation, SEGA Saturn, Windows - 255 votes
* Hexen: Deathkings of the Dar kCitadel (1996) DOS, Macintosh, Windows - 183 votes
* Hexen II (1997) Macintosh, Windows - 291 votes
* Hexen II: Portal of Praevus (1998) Windows - 238 votes
* High Seas Trader (1995) Amiga, DOS
* The Hobbit (2003) GameCube, PlayStation 2, Windows, Xbox
* The Hulk (2003) GameCube, PlayStation 2, Windows, Xbox
* HyperBlade (1996) Windows
I
* Inca I & II (1995) DOS, Windows
* The Incredible Machine (1992) 3DO, DOS, Macintosh - 223 votes
* The Incredible Machine (1994) DOS, Macintosh - 161 votes
* The Incredible Toon Machine (1994) Macintosh, Windows
* IndyCar Racing (1993) DOS
* IndyCar Racing II (1996) DOS, Macintosh, Windows
* Interstate '82 (1999) Windows - 212 votes
* The Island of Dr. Brain (1992) DOS
J
* Jack Nicklaus 6: Golden Bear Challenge (1999) Windows
* Jurassic Park: Operation Genesis (2003) PlayStation 2, Windows, Xbox
K
* King's Quest: Quest for the Crown (1984) Amiga, Apple II, Apple IIgs, Atari ST, DOS, Macintosh, PC Booter, SEGA Master System - 343 votes
* King's Quest II: Romancing the Throne (1985) Amiga, Apple II, Apple IIgs, Atari ST, DOS, PC Booter - 341 votes
* King's Quest III: To Heir is Human (1986) Amiga, Apple II, Apple IIgs, Atari ST, DOS, TRS-80 CoCo - 334 votes
* King's Quest: Mask of Eternity (1998) Windows - 284 votes
L
* Laser Surgeon: The Microscopic Mission (1987) DOS
* The Last Dynasty (1995) DOS, Windows
* Lawnmower Racing Mania 2007 (2006) Windows I lolled!
* Leather Goddesses of Phobos (1988) Apple II, DOS
* Leather Goddesses of Phobos 2 (1992) DOS
* Legendary Lords (2000) Windows
* Leisure Suit Larry Collection (2001) Windows
* Leisure Suit Larry 7: Love for Sail! - 319 votes
* Leisure Suit Larry: Ultimate Pleasure Pack (1999) DOS, Windows - 190 votes
* Lighthouse: The Dark Being (1996) DOS, Macintosh, Windows
* The Lost Mind of Dr. Brain (1995) Macintosh, WIndows
* The Lost Treasures of Infocom (1991) DOS, Macintosh
* The Lost Treasures of Infocom II (1992) DOS, Macintosh
M
* Mageslayer (1997) Windows
* Mat Hoffman's Pro BMX (2001) Dreamcast, Game Boy Advance, Game Boy Color, PlayStation, Windows
* Metaltech: Earthsiege (1994) DOS - 130 votes
* Metaltech: Battledrome (1995) DOS
* Mindfighter (1988) DOS
* Missionforce: CyberStorm (1996) Windows
* Mixed-Up Mother Goose Deluxe (1995) Windows
* The Movies (2005) Windows (Maybe Lionhead Studios?)
* Muppet Treasure Island (1996) Macintosh, Windows, Windows 3.x
* The Mystery Collection (1995) DOS, Macintosh
N
* NASCAR Racing Series
* Necrodome (1996) Windows
* NetMech (1996) DOS, Macintosh, Windows
* NetStorm: Islands At War (1997) Windows
* No One Lives Forever: Game of the Year Edition (2001) Windows - 358 votes
* No One Lives Forever 2: A Spy in H.A.R.M.'s Way (2002) Windows - 657 votes
O
* Ocean Ranger (1988) Commodore 64, DOS
* The Operative: No One Lives Forever (2000) Windows - 608 votes
* Outdoor Trivia Challenge (1997) Windows
P
* Paparazzi!: Tales of Tinseltown (1995) DOS, Macintosh, Windows, Windows 3.x
* Pharaoh (1999) Windows - 166 votes
* Pharaoh Gold (2001) Windows
* Pitfall: The Mayan Adventure (1994) Game Boy Advance, Genesis, Jaguar, Sega 32X, Sega CD, SNES, Windows
* Police Quest Collection (2006) Windows - 316 votes
* Police Quest: SWAT (1995) DOS, Macintosh, Windows - 173 votes
* Police Quest: SWAT 2 (1998) Windows - 153 votes
* Poseidon: Master of Atlantis (2001) Windows
* PowerHits: BattleTech (1992) DOS
* PowerHits Movies (1992) DOS
* PowerHits Sci/Fi (1994) DOS
* PowerHits Sports (1992) DOS
Q
* Quest for Glory Anthology (1996) DOS, Windows - 366 votes
R
* Return to Castle Wolfenstein (2001) Action Windows - 288 votes
* Return to Zork (1993) Adventure 3DO, DOS, Macintosh, PlayStation, Saturn, Windows - 212 votes
* Roberta Williams' King's Quest I: Quest for the Crown (1990) Amiga, DOS
* Roberta Williams' King's Quest VII: The Princeless Bride (1994) DOS, Macintosh, Windows - 338 votes
S
* Santa Fe Mysteries: Sacred Ground (1997) Adventure DOS, Macintosh, Windows
* Santa Fe Mysteries: The Elk Moon Murder (1996) Adventure DOS, Macintosh, Windows
* Sargon 5: World Class Chess (1991) Strategy DOS
* The Sci-Fi Collection (1995) Adventure DOS, Macintosh
* ShadowsCaster (1993) DOS
* Shanghai (1986) Strategy Amiga, Amstrad CPC, Apple II, Atari 8-bit, Atari ST, Commodore 64, DOS, Lynx, Macintosh, MSX, Sega Master System, TRS-80 CoCo
* Shanghai: Dynasty (1997) Strategy Macintosh, Windows
* Shanghai: Great Moments (1995) Strategy Windows, Windows 3.x
* Shanghai II: Dragon's Eye (1989) Strategy DOS, Genesis, MSX, SNES, Windows, Windows 3.x
* Shanghai: Mah-Jongg Essentials (1999) Strategy Macintosh, Windows
* Shanghai: Second Dynasty (1999) Strategy Macintosh, Windows
* Shivers (1995) Macintosh, Windows
* Shivers 2: Harvest of Souls (1997) Windows
* Sid & Al's Incredible Toons (1993) DOS
* Soldier of Fortune (2000) Action Windows - 218 votes
* Soldier of Fortune II: Double Helix (2002) Action Windows, Xbox - 172 votes
* Space Bucks (1996) Windows
* Space Quest: The Sarien Encounter (1986) Amiga, Aplle II, Atari ST, DOS, Macintosh - 308 votes
* Space Quest II: Vohaul's Revenge (1987) Amiga, Aplle II, Atari ST, DOS, Macintosh - 317 votes
* Space Quest III: The Pirates of Pesulon (1989) Amiga, DOS, Macintosh, Windows - 321 votes
* Spider-Man (2000) Action Dreamcast, Game Boy Color, Nintendo 64, PlayStation, Windows
* Spider-Man 2 (2004) Action Windows, Nintendo DS, GameCube, PlayStation 2, PSP, Xbox
* Spider-Man: The Movie (2002) Action Game Boy Advance, GameCube, PlayStation 2, Windows, Xbox
* Spycraft: The Great Game (1996) Action, Adventure, Role-Playing (RPG), Simulation, Strategy DOS, Macintosh, Windows
* Starsiege (1998) Windows - 152 votes
* Starsiege: Tribes (1998) Windows - 251 votes
* Star Rank Boxing II (1987) Action, Sports Apple II, Commodore 64, DOS
* Star Trek Action Pack (2002) Action, Simulation, Strategy Windows
* Star Trek: Armada (2000) Strategy Windows - 234 votes
* Star Trek: Armada II (2001) Strategy Windows - 228 votes
* Star Trek: Away Team (2001) Strategy Windows - 170 votes
* Star Trek: Bridge Commander (2002) Action, Simulation, Strategy Windows - 284 votes
* Star Trek: ConQuest Online (2000) Strategy Windows
* Star Trek: Elite Force II (2003) Action Windows - 250 votes
* Star Trek: Hidden Evil (1999) Action, Adventure Windows - 125 votes
* Star Trek: Starfleet Command III (2002) Action, Adventure, Simulation, Strategy Windows - 232 votes
* Star Trek: Voyager – Elite Force (2000) Action, Adventure Windows - 265 votes
* Supercar Street Challenge (2001) Racing / Driving PlayStation 2, Windows
* SWAT 3: Tactical Game of the Year Edition (2001) Windows - 148 votes
* SWAT 4: Gold Edition (2006) Windows - 188 votes
T
* Time Commando (1996) Action, Adventure DOS, PlayStation, Windows - 105 votes
* The Time Warp of Dr. Brain (1996) Macintosh, Windows
* Tongue of the Fatman (1989) Action Commodore 64, DOS
* Tony Hawk's Pro Skater 2 (2000) Action, Sports Dreamcast, Game Boy Advance, Game Boy Color, Nintendo 64, PlayStation, Windows
* Tony Hawk's Pro Skater 3 (2001) Sports Game Boy Advance, Game Boy Color, GameCube, Nintendo 64, PlayStation, PlayStation 2, Windows, Xbox
* Tony Hawk's Underground 2 (2004) Sports Game Boy Advance, GameCube, PlayStation 2, Windows, Xbox
* Torin' Passage (1995) DOS, Macintosh, Windows
* The Tracer Sanction (1984) Adventure Apple II, Commodore 64, DOS
* Tribes 2 (2001) Linux, Windows - 184 votes
* Tribes: Vengeance (2004) Windows - 132 votes
* True Crime: New York City (2005), GameCube, PlayStation 2, Windows, Xbox
* True Crime: Streets of LA (2003) Action, Adventure, Racing / Driving GameCube, PlayStation 2, Windows, Xbox
U
* UFO (1989) DOS
* Ultimate Spider-Man (2005) Action GameCube, PlayStation 2, Windows, Xbox
* Urban Runner (1996) DOS, Windows
V
* Vampire: The Masquerade – Bloodlines (2004) Action, Role-Playing (RPG) Windows - 704 votes
W
* Wishbringer (1988) Adventure Commodore 64, DOS
* Wizards & Warriors (2000) Adventure, Role-Playing (RPG) Windows - 148 votes
* Wolfenstein: Enemy Territory (2003) Action Linux, Macintosh, Windows - 148 votes
X
* X2: Wolverine's Revenge (2003) Action Game Boy Advance, GameCube, PlayStation 2, Windows, Xbox
* X-Men Legends II: Rise of Apocalypse (2005) Action, Role-Playing (RPG) GameCube, PlayStation 2, PSP, Windows, Xbox
Y
* You Don't Know Jack Series - 100 votes
Z
* Zeliard (1987) DOS
* Zeus: Master of Olympus (2000) Windows - 109 votes
* Zork Classics: Interactive Fiction (2000) Adventure Windows - 195 votes
* Zork: Grand Inquisitor (1997) Adventure Macintosh, Windows - 221 votes
* Zork Legacy Collection (1997) Adventure DOS, Windows - 211 votes
* Zork Nemesis: The Forbidden Lands (1996) Adventure DOS, Macintosh, Windows - 211 votes
* Zork: The Undiscovered Underground (1997) Adventure Macintosh, Windows
I hope someone finds this interesting and that I'm not just wasting my time.
<update>I removed Blizzard from the list since Navagon pointed out that Blizzard isn't in on the deal. Also I've already removed all titles by iD, Valve and LucasArts, since it's highly unlikely that Activision has the rights for those.
I've also added No One Lives forever, Heretic, Hexen, and Tribes, as well as some other Vivendi games and removed the Lords of magic/the Realm series</update>
<update>I've updated the list since the release of Phantasmagoria 1 and Space Quest 4-6.</update>

Thanks for taking the time to put that together. Some amazing titles there.

Hi Duffadash
Thanks for the list, I found it very interesting.
Cheers
Mark

I find it interesting that the users of gog.com is more interested in the MechWarrior games, than Diablo 1, StarCraft, Sierra's old adventure games and Infocom's text adventures...

Perhaps a lot of users already own Diablo and Starcraft? And wasn't there some issue with the old Mechwarrior games not being able to run anymore? Personally i would love to be able to play the Mech games again.

I think it may be due to people being realistic about Blizzard releasing the older Diablo/Starcraft titles to anyone else for release. Activision may hold (or have held) the publishing rights, but Blizzard holds the IP and has a huge say in who does what with them.

Just as a heads up: Blizzard aren't a part of this deal. Whether that means they will soon follow, or they'll never be swayed, I don't know. But there won't be any of their games as a part of this Activision Month.

I kindda figured that, but I was still hoping... Anyways, I'm going to bed now, I'll update the list when I wake up.

Oh dear my wallet is going to take a battering.

Interstate '76 was great.

The reason StarCraft and Warcraft aren't on here is because you can still get them on Blizzard's website, and they update their old games so they work on modern computers.

Great list but there are some things missing. First, there are old Raven games like Hexen and Heretic (I'm not sure about all instalments but my Heretic 2 CD only has Raven and Activision logos). Second is No one lives forever games - Sierra held the rights last time I checked.

We already have Lords of Magic and Lords of the Realm series

What he says. Rights belong to Rebellion nowadays and they are already available here. There are probably more like that but they are likely to own rights to games not on the list.
Edit: Call to Power II has 152 votes (may be more as there are two entries: Call to Power II and Civilization: Call to Power II, first is correct name)
Edit 2: Empire Earth also belongs to Rebellion and is available here