Region | Title | System | Version | Edition | Languages | Serial | Status |
| OverBlood | PSX | | Original | | SLUS-00464 | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 2) | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games (Disc 1) | PC | | Original | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| Outpost | PC | 1.5 | Rerelease, Sierra Originals | | | |
| Outpost | PC | | Original | | S725430 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Original | | 9511831 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Original | | 9511830 | |
| Outlaws (Disc 1) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644430 | |
| Outcast (Disc 1) | PC | | Original | | 42831-9110TC | |
| Out of This World | 3DO | RE | 3DO Maniac Pack | | | |
| Out of This World | 3DO | | Original | | | |
| The Original Links | PC | | Solid Gold Edition | | | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| The Oregon Trail | PC | 1.2 | Original | | #HCD706 | |
| Oregon Trail II: 25th Anniversary Limited Edition | PC | 1.3 | Original, SoftKey | | #OTR744AE-CD | |
| Oregon Trail II | PC | 1.31 | Rerelease | | #HCD744AE-CD | |
| Oregon Trail II | PC | 1.31 | Rerelease | | HCD744BE-CD | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 381032-CD/i401ha | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.1 | Rerelease, Southwestern School Set | | 380859B-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859-CD | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1.1 | Rerelease | | OTF744BE-CD3 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1.1 | Rerelease | | OTF744BE-CD2 | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1.1 | Rerelease | | OTF744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | | Original | | OTA744AE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.0 | Original | | OTA744AE-CD1 | |
| The Operative: No One Lives Forever (Disc 2) | PC | 1.0 | Original | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.004 | Game of the Year Edition | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | 1.0 | Original | | | |
| Operation Flashpoint: Resistance | PC | 1.75 | Original | | MOFRCDUS00 | |
| Operation Flashpoint: Gold Upgrade | PC | 1.30 | Original | | MOFUCDUS00 | |
| Operation Flashpoint: Cold War Crisis | PC | 1.0 | Original | | MOPFCDUS00 | |
| Operation | PC | | General Mills | | AM801R5 | |
| OnSide Soccer | 3DO | | Unlicensed (oldergames, Good Deal Games Double Header! Two Game Set) | | | |
| Online Start-Up Disc v3.5: Broadband Only | PS2 | 1.00 | Original | | PBPX 95247 | |
| Online Start-Up Disc v3.0 | PS2 | 1.01 | | | PBPX-95242 | |
| Online Start-Up Disc v3.0 | PS2 | 1.01 | | | SCUS 97425 | |
| Online Start-Up Disc v1.0 Disco de Inicio en Línea v1.0 | PS2 | 1.00 | Original | | PBPX 95250 … | |
| Online Start-Up Disc 4.0: Broadband Only | PS2 | 1.02 | Bundled with PS2 | | PBPX 95248 … | |
| Online Start-Up Disc 4.0 | PS2 | 1.00 | | | SCUS-97357 | |
| Oni | PS2 | 1.20 | Original | | SLUS-20064 | |
| Oni | PC | 1.0 | Original | | | |
| One Unit Whole Blood | PC | 1.21 | Original | | 04-16459CD1 | |
| One Piece Mansion | PSX | | Original | | SLUS-01406 | |
| One | PSX | | Original | | SLUS-00469 | |
| Ominous Horizons Ominous Horizons: A Paladin's Calling | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 3) | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 2) | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul (Disc 1) | PC | 1.0 | Original | | | |
| Omikron: The Nomad Soul | DC | 1.001 | Original | | T-36807N | |
| Omega Boost | PSX | | Original | | SCUS-94449 | |
| Omar Sharif Bridge | PC | 1.0 | Original | | | |
| Olympic Summer Games | PSX | | Original | | SLUS-00148 | |
| Olympic Summer Games | 3DO | | Original | | FZ-SW0012 | |
| Olympic Soccer | 3DO | | Original | | FZ-SW0011 | |
| Olympic Soccer | PSX | | Original | | SLUS-00156 | |
| Okage: Shadow King | PS2 | 1.01 | Original | | SCUS 97129 | |
| Oil Tycoon | PC | 1.01 | Original | | | |
| Ohio Distinctive Software Vol. I | PC | | | | | |
| Ogre Battle: Limited Edition | PSX | | Original | | SLUS-00467 | |
| Official U.S. PlayStation Magazine Demo Disc 54 | PSX | | | | SCUS-94664 | |
| Official U.S. PlayStation Magazine Demo Disc 52 | PSX | | | | SCUS-94662 | |
| Official U.S. PlayStation Magazine Demo Disc 50 | PSX | | | | SCUS-94658 | |
| Official U.S. PlayStation Magazine Demo Disc 48 | PSX | | | | SCUS-94655 | |
| Official U.S. PlayStation Magazine Demo Disc 47 | PSX | | | | SCUS-94652 | |
| Official U.S. PlayStation Magazine Demo Disc 46 | PSX | | | | SCUS-94649 | |
| Official U.S. PlayStation Magazine Demo Disc 45 | PSX | | | | SCUS-94645 | |
| Official U.S. PlayStation Magazine Demo Disc 44 | PSX | | | | SCUS-94637 | |
| Official U.S. PlayStation Magazine Demo Disc 43 | PSX | EDC | | | SCUS-94634 | |
| Official U.S. PlayStation Magazine Demo Disc 43 | PSX | | | | SCUS-94634 | |
| Official U.S. PlayStation Magazine Demo Disc 42 | PSX | | | | SCUS-94631 | |
| Official U.S. PlayStation Magazine Demo Disc 41 | PSX | | | | SCUS-94630 | |
| Official U.S. PlayStation Magazine Demo Disc 40 | PSX | | | | SCUS-94628 | |
| Official U.S. PlayStation Magazine Demo Disc 39 | PSX | | | | SCUS-94622 | |
| Official U.S. PlayStation Magazine Demo Disc 38 | PSX | | | | SCUS-94617 | |
| Official U.S. PlayStation Magazine Demo Disc 37 | PSX | | | | SCUS-94614 | |
| Official U.S. PlayStation Magazine Demo Disc 36 | PSX | | | | SCUS-94599 | |
| Official U.S. PlayStation Magazine Demo Disc 35 | PSX | | | | SCUS-94596 | |
| Official U.S. PlayStation Magazine Demo Disc 34 | PSX | | | | SCUS-94593 | |
| Official U.S. PlayStation Magazine Demo Disc 33 | PSX | | | | SCUS-94591 | |
| Official U.S. PlayStation Magazine Demo Disc 32 | PSX | | | | SCUS-94583 | |
| Official U.S. PlayStation Magazine Demo Disc 31 | PSX | | | | SCUS-94499 | |
| Official U.S. PlayStation Magazine Demo Disc 30 | PSX | | | | SCUS-94438 | |
| Official U.S. PlayStation Magazine Demo Disc 29 | PSX | | | | SCUS-94437 | |
| Official U.S. PlayStation Magazine Demo Disc 28 | PSX | | | | SCUS-94436 | |
| Official U.S. PlayStation Magazine Demo Disc 27 | PSX | | | | SCUS-94435 | |
| Official U.S. PlayStation Magazine Demo Disc 26 | PSX | | | | SCUS-94434 | |
| Official U.S. PlayStation Magazine Demo Disc 25 | PSX | | | | SCUS-94433 | |
| Official U.S. PlayStation Magazine Demo Disc 24 | PSX | | | | SCUS-94432 | |
| Official U.S. PlayStation Magazine Demo Disc 23 | PSX | | | | SCUS-94431 | |
| Official U.S. PlayStation Magazine Demo Disc 22 | PSX | | | | SCUS-94430 | |
| Official U.S. PlayStation Magazine Demo Disc 21 | PSX | | | | SCUS-94429 | |
| Official U.S. PlayStation Magazine Demo Disc 20 | PSX | | | | SCUS-94282 | |
| Official U.S. PlayStation Magazine Demo Disc 19 | PSX | | | | SCUS-94281 | |
| Official U.S. PlayStation Magazine Demo Disc 18 | PSX | | | | SCUS-94280 | |
| Official U.S. PlayStation Magazine Demo Disc 17 | PSX | | | | SCUS-94279 | |
| Official U.S. PlayStation Magazine Demo Disc 16 | PSX | | | | SCUS-94278 | |
| Official U.S. PlayStation Magazine Demo Disc 15 | PSX | | | | SCUS-94277 | |
| Official U.S. PlayStation Magazine Demo Disc 14 | PSX | | | | SCUS-94276 | |
| Official U.S. PlayStation Magazine Demo Disc 13 | PSX | | | | SCUS-94275 | |
| Official U.S. PlayStation Magazine Demo Disc 12 | PSX | | | | SCUS-94219 | |
| Official U.S. PlayStation Magazine Demo Disc 11 | PSX | | | | SCUS-94218 | |
| Official U.S. PlayStation Magazine Demo Disc 10 | PSX | | | | SCUS-94217 | |
| Official U.S. PlayStation Magazine Demo Disc 09 | PSX | | | | SCUS-94216 | |
| Official U.S. PlayStation Magazine Demo Disc 08 | PSX | | | | SCUS-94215 | |
| Official U.S. PlayStation Magazine Demo Disc 07 | PSX | | | | SCUS-94214 | |
| Official U.S. PlayStation Magazine Demo Disc 06 | PSX | | | | SCUS-94213 | |
| Official U.S. PlayStation Magazine Demo Disc 05 | PSX | | | | SCUS-94212 | |
| Official U.S. PlayStation Magazine Demo Disc 04 | PSX | | | | SCUS-94211 | |
| Official U.S. PlayStation Magazine Demo Disc 03 | PSX | | | | SCUS-94210 | |
| Official U.S. PlayStation Magazine Demo Disc 02 | PSX | | | | SCUS-94198 | |
| Official U.S. PlayStation Magazine Demo Disc 01 | PSX | | | | SCUS-94189 | |
| Official Sega Dreamcast Magazine: Special Edition Preview PC CD-ROM | PC | | | | | |
| The Official Guide to Babylon 5 The Official Guide to J. Michael Straczynski's Babylon 5 | PC | | Original | | | |
| Off-World Interceptor Extreme | PSX | | Original | | SLUS-00020 | |
| ODS Robot Challenge | PC | 5.0.1r26 | Teacher's Edition | | | |
| Odium ōdi·um | PC | | Original | | CD-W58-1104-0 | |
| Odell Down Under | PC | | Original, SoftKey | | POD544AE-CD | |
| Oddworld: Abe's Oddysee | PSX | Rev 2 | Greatest Hits | | SLUS-00190 | |
| Oddworld: Abe's Oddysee | PSX | Rev 1 | Original, Greatest Hits | | SLUS-00190 | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Original | | 04-12608CD | |
| Oddworld: Abe's Oddysee | PSX | | Original | | SLUS-00190 | |
| Oddworld: Abe's Oddysee | PSX | | Demo | | SLUS-90004 | |
| Oddworld: Abe's Exoddus (Disc 2) | PSX | | Original | | SLUS-00731 … | |
| Oddworld: Abe's Exoddus (Disc 1) | PSX | | Original | | SLUS-00710 … | |
| Oddworld: Abe's Exoddus (Install) | PC | 2.0 | Original | | 04-15993CD1 | |
| Oddworld: Abe's Exoddus (Play) | PC | | Original | | 04-15993CD2 | |
| Oceans Below | 3DO | | Original | | | |
| Oceans Below The Software Toolworks Presents ... Oceans Below | MAC | | Original | | 2198620-590001 / I 073100, CDRM1103420 | |
| Obsidian (Disc 5) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 4) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 3) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 2) | PC | | Original, Complimentary Copy | | 11008 | |
| Obsidian (Disc 1) | PC | | Original, Complimentary Copy | | 11008 | |
| O.D.T. | PSX | | Original | | SLUS-00698 | |
| O.D.T. | PSX | | Demo | | SLUS-90043 | |
| Ozzie's World | PC | | Original | | | |
| Oz: The Magical Adventure | PC | 7.0.0.198 | Rerelease | | 92785 | |
| Oz: The Magical Adventure | PC | | Original | | | |
| Over 200 Programs for Windows STG Computers LTD Windows Extra CD-ROM | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games: Volume II (Disc 2) Over 1000 Games Volume 2 | PC | | Original | | | |
| Over 1000 Games: The Complete Encyclopedia of Games: Volume II (Disc 1) Over 1000 Games Volume 2 | PC | | Original | | | |
| Outwars (Disc 2) | PC | 1.0 | Original | | 0298 Part No. X03-57509 | |
| Outwars (Disc 1) | PC | 1.0 | Original | | 0298 Part No. X03-63527 | |
| Outtrigger | DC | 1.003 | Original | | 51102 | |
| OutRun 2006: Coast 2 Coast (Disc 2) | PC | | Original | | | |
| OutRun 2006: Coast 2 Coast (Disc 1) | PC | | Original | | | |
| Outpost 2: Divided Destiny | PC | 1.2.0.5 | Original | | | |
| Outpost | PC | 1.1 | Rerelease | | S725431 | |
| Outlive | PC | 1.01 | Original | | | |
| Outlaws: Cidade Sem Lei (Disc 2) | PC | 2.0 | Original | | 0806.06.0 | |
| Outlaws: Cidade Sem Lei (Disc 1) | PC | 2.0 | Original | | 0806.05.0 | |
| Outlaws (Disc 2) | PC | 2.0 | Rerelease | | 9511831 | |
| Outlaws (Disc 2) | PC | 1.0 Build 3 | Bundle Version Diamond OEM | | 644431 | |
| Outlaws (Disc 1) | PC | 2.0 | Rerelease | | 9511830 | |
| Outlaws (Demonstration Program) | PC | Demo 1.0 CD Build 3 | Demo | | 644230 | |
| Outlast: A Reading for Information Game | PC | | Original | | HH824 | |
| Outcry (Disc 2) Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |
| Outcry (Disc 1) Outcry: The Dawn | PC | Version DPV 1.0 | Original | | PCO596CD | |
| Outcast (Disc 2) | PC | | Original | | 42831-9110TC | |
| Outburst | PC | | Classic Value Series | | Product# 99043 | |
| Out of This World | PC | | Valueware | | CD-ICD-142-0 | |
| Out of This World | PC | | Rerelease | | CD-MMC-023-0 | |
| Ouro e Glória: O Caminho para El Dorado | PC | | Original | | 906.02.0 | |
| Our House featuring The Family Circus | VIS | | Original | | 25-6146 | |
| Othello | PC | | Original | | 99011 | |
| OSHA MHE Forklifts OSHA MHE Forklifts: PFS Interactive Training | CDI | | Original | | | |
| Oscar Wilde's The Selfish Giant | PC | 2.10 | Original | | MQ 13-004-144 | |
| Oro Negro: Juego de Guerra y Estrategia | PC | | Covermount | | | |
| Orly's Draw-A-Story | PC | | Original | | | |
| The Orion Conspiracy | PC | 1.01 | Original | | | |
| Original Xbox Game Support: December 2005 (1.2) Prise en charge des jeux Xbox d'origine: Décembre 2005 (1.2) | XBOX360 | | Original | | | |
| Original Xbox Game Support: August 2006 (1.5) | XBOX360 | | | | | |
| The Original Mulan 花木兰 | PC | | Original | | | |
| The Oregon Trail: Classic Edition | PC | 3.0.1 | SoftKey | | POT144CE-CD | |
| The Oregon Trail: Classic Edition | PC | | SoftKey | | POT144BE-CD | |
| The Oregon Trail: Classic Edition | PC | | SoftKey | | POT144EE-CD | |
| The Oregon Trail | PC | 3.0.1 | Slash | | CDRM1239790 | |
| The Oregon Trail | PC | 1.22 | Smart Saver | | ORT844AE-CD | |
| The Oregon Trail | PC | 1.21 | | | | |
| The Oregon Trail | PC | 1.1 | Original | | #HCD606 | |
| The Oregon Trail | PC | 1.0 | Original | | | |
| Oregon Trail II + Logic Quest | PC | 1.2/1.0 | Original | | | |
| Oregon Trail II | PC | 1.32 | Rerelease | | #HCD744CE-CD | |
| Oregon Trail II | PC | 1.3 | Smart Saver | | 0TT744AE-CD | |
| Oregon Trail II | PC | 1.0 | Original | | | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.01E | Enhanced Education Version | | 480599-CD | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Scholastic | | 380859-CD WP2 | |
| The Oregon Trail 5th Edition: Adventures Along the Oregon Trail | PC | 1.0 | Original | | 380859A-CD | |
| The Oregon Trail 4th Edition (Disc 3) | PC | 1 | Original | | OTF744AE-CD3 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Rerelease | | OTF744CE-CD2 | |
| The Oregon Trail 4th Edition (Disc 2) | PC | 1 | Original | | OTF744AE-CD2 | |
| The Oregon Trail 4th Edition (Disc 1) | PC | 1 | Original | | OTF744AE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.3 | The Learning Company | | OAE744BE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | 1.2 | Original | | OTA744BE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 3) | PC | | Original | | OTA744AE-CD3 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.3 | The Learning Company | | OAE744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 2) | PC | 1.2 | Original | | OTA744BE-CD2 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.3 | The Learning Company | | OAE744BE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2a | Bundle Version Compaq Presario OEM | | | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Original | | OTA744CE-CD1 | |
| The Oregon Trail 3rd Edition: Pioneer Adventures (Disc 1) | PC | 1.2 | Rerelease | | OTA744BE-CD1 | |
| Orbatak | 3DO | | Arcade CD-ROM | | | |
| Optimum Resource Sampler | PC | | Rerelease | | | |
| Optimum Resource Sampler | PC | | Original | | | |
| OptImage Media Showcase | CDI | 1.0 | Original | | | |
| OptImage CD-I Starter System: Sampler Disc: Version 1.1 | CDI | | | | | |
| OptImage CD-I 220 Adjustment Disc | CDI | | Original | | | |
| Opsys | PC | | Original | | | |
| The Operative: No One Lives Forever (Disc 2) (In the Lounge with No One Lives Forever) | PC | | Bundle Version Micro-Star International OEM | | CD-W581995-MSYZ2 | |
| The Operative: No One Lives Forever (Disc 1) (Game Disc) | MAC | 1.004 | MacPlay | | | |
| The Operative: No One Lives Forever (Disc 1) | PC | | Bundle Version Micro-Star International OEM | | CD-W581995-MSYZ1, FXX08903223D1 | |
| The Operational Art of War: Century of Warfare | PC | | Original | | | |
| Operation Omega | PC | | Original | | 7-20286-92175-1 | |
| Operation Neptune + Reader Rabbit 2 Deluxe! + Ultimate Writing & Creativity Center The Learning Company 3-in-1 | PC | | | | | |
| Operation Neptune | PC | 1.23 | The ClueFinders: Math Ages 9-12 | | ONT744EE-CD | |
| Operation Neptune | PC | 1.22 | Original | | ONT744CE-CD | |
| Operation Flashpoint: Cold War Crisis | PC | | Playable Demo | | POPFCDUS40 | |
| Operation Europe: Path to Victory 1939-45 | PC | | Original | | | |
| Operation Body Count: One Level Preview | PC | | Original | | | |
| Operation Body Count | PC | | Original | | | |
| Operation | PC | | General Mills | | AM0703R71 | |
| Operation | PC | | General Mills | | | |
| Opening Night: Behind The Scenes | PC | 1.0 | Original | | #HCD646B | |
| Opening Night | PC | 1.0 | Original | | #HCD646A | |
| Open Season (Disc 3) | PC | 1.0 | Original | | 683131-CD3 | |
| Open Season (Disc 2) | PC | 1.0 | Original | | 683131-CD2 | |
| Open Season (Disc 1) | PC | 1.0 | Original | | 683131-CD1 | |
| Ooga Booga | DC | 1.001 | Original | | 51140 | |
| Online Start-Up Disc v3.5: Broadband Only | PS2 | 1.00 | Original | | PBPX-95246 | |
| Online Start-Up Disc v3.0 | PS2 | 1.02 | Original | | PBPX-95239 | |
| Online Connection CD: For the PlayStation Game Console | PSX | | Beta Trial Version 1.0 | | LSP-150500 … | |
| Onimusha 3: Demon Siege (Disc 3) | PC | | Original | | 683100-CD3 | |
| Onimusha 3: Demon Siege (Disc 2) | PC | | Original | | 683100-CD2 | |
| Onimusha 3: Demon Siege (Disc 1) | PC | | Original | | 683100-CD1 | |
| Oni / 4x4 Evo Oni / 4x4 Evolution | PC | | Demo | | 12DC1-09GM03-11 | |
| Oni | MAC | | Original | | | |
| OnHand Sports Games / Sega Swirl Lite | PALM | PDA105-01 | OnHand Double Pack (Sports Games/Astrologer) | | PDA105-01 | |
| OnHand Complete Astrologer OnHand Complete Astrologer: Horoscopes & More! | PALM | PDA108-01 | OnHand Double Pack (Sports Games/Astrologer) | | PDA108-01 | |
| OnHand Chess / Sega Swirl Lite | PALM | PDA103-01 | Original | | PDA103-01 | |
| One Must Fall: Battlegrounds | PC | 2090 | Original | | | |
| One Must Fall 2097 | PC | 1.1 | Demo | | | |
| One Must Fall 2097 | PC | | Original | | EPOMF01 | |
| One Must Fall 2097 | PC | | Original | | EPOMF01 | |
| The Omega Stone: Riddle of the Sphinx II (Disc 4) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 3) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 2) | PC | 1.2.3.2 | Original | | | |
| The Omega Stone: Riddle of the Sphinx II (Disc 1) | PC | 1.2.3.2 | Original | | | |
| Omar Sharif on Bridge | PC | | Valueware | | CD-ICD-148-0 | |
| Olympic Soccer | SS | 2.000 | Original | | T-7904H | |
| Old El Paso Recipes for Family Fun | PC | | Original | | | |
| Official Sega Dreamcast Magazine Vol. 9: December 2000 | DC | 1.000 | | | IGN9 | |
| Official Sega Dreamcast Magazine Vol. 8: November 2000 | DC | 1.020 | | | IGN8 | |
| Official Sega Dreamcast Magazine Vol. 7: September 2000 | DC | 1.020 | | | IGN7 | |
| Official Sega Dreamcast Magazine Vol. 6: July 2000 | DC | 1.050 | | | IGN6 | |
| Official Sega Dreamcast Magazine Vol. 5: May 2000 | DC | 1.010 | | | | |
| Official Sega Dreamcast Magazine Vol. 4: March 2000 | DC | 1.020 | | | IGN3 | |
| Official Sega Dreamcast Magazine Vol. 3: January 2000 | DC | 1.010 | | | IGN2 | |
| Official Sega Dreamcast Magazine Vol. 2: November 1999 | DC | 1.020 | | | IGN1 | |
| Official Sega Dreamcast Magazine Vol. 11: February 2001 | DC | 0.500 | | | | |
| Official Sega Dreamcast Magazine Vol. 10: January 2001 | DC | 1.200 | | | IGN10 | |
| Official Lara Croft: Real Life '99 Lara: Character Images | PC | | Press Kit | | | |
| The Official Guide to The Daedalus Encounter: Companion Disc | PC | | Original | | | |
| Official Duke Nukem 3D Level Design Handbook | PC | | Original | | 1869-0 | |
| The Official Browser of Primagames.com | PC | | | | | |
| The Office | PC | | Original | | | |
| Off-World Interceptor Extreme | SS | 1.000 | Original | | T-15908H | |
| Off-Road Redneck Racing | PC | | Original | | CD-C98-1259-0 | |
| Of Light and Darkness: The Prophecy (Disc 3) | PC | | Original | | CD-C95-166-2 | |
| Of Light and Darkness: The Prophecy (Disc 2) | PC | | Original | | CD-C95-166-1 | |
| Of Light and Darkness: The Prophecy (Disc 1) | PC | | Original | | CD-C95-166-0 | |
| Odyssey: The Search for Ulysses (Disc 2) | PC | | Original | | | |
| Odyssey: The Search for Ulysses (Disc 1) | PC | | Original | | | |
| Odyssey: The Legend of Nemesis | MAC | 1.0 | Original | | | |
| ODS Robot Challenge | PC | | Original | | | |
| ODS Carnival Math | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Carnival Math | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Amazing Art Corner | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Air Explorer | PC | 5.0r134 | Teacher's Edition | | | |
| ODS Air Explorer | PC | 5.0r134 | Teacher's Edition | | | |
| Oddworld: Abe's Oddysee | PC | 2.0 | Channelware | | 04-15303 | |
| Oddworld: Abe's Oddysee | PSX | | Trade Demo | | | |
| Oceans Below | PC | | Bundle Version OEM | | RVL 13-004-059 Rev. A / 2198610-590002 / I 083100 | |
| Obsidian (Disc 5) | PC | | Original | | 11008 | |
| Obsidian (Disc 1) | PC | | Original | | 11008 | |
| Obsidian | PC | 1.0 | Demo | | | |
| ObsCure (Disc 5) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 4) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 3) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 2) | PC | 1.0 | Original | | PCO457CD | |
| ObsCure (Disc 1) | PC | 1.0 | Original | | PCO457CD | |
| O.R.B: Off-World Resource Base | PC | 1.0 | Original | | 22434CD | |