| Title |
Publisher |
Year |
Language |
Documents |
| Obituario |
Santiago Eximeno |
2002 |
Spanish |
|
| Ocaso Mortal |
Dhan |
2001 |
Spanish |
|
| Odieus' Quest for the Magic Flingshot |
CTH Enterprises , Grim Reaper, The  |
1988 |
English |
Solution |
| Of Forms Unknown |
Chris Markwyn |
1996 |
English |
|
| Offensive Probing |
Benjamin Richard "Yahtzee" Croshaw  |
1999 |
English |
Solution |
| Ofrenda a la Pincoya |
Sebastian Armas  |
2008 |
Spanish |
|
| Oily Deeps, The |
John Cater |
1999 |
English |
Map, Solution |
| Old Jim's Convenience Store |
Anssi Räisänen |
2019 |
English |
|
| Old Sherwood Cemetary, The |
Duchess |
2002 |
English |
Map, Solution |
| Olvido Mortal |
Andrés Viedma Peláez |
2000 |
Spanish |
|
| OMNIQuest |
Chris Barden, Chris Ethridge |
1988 |
English |
Hints, Map |
| On Optimism |
Zach Flynn  |
2005 |
English |
Solution |
| Once in a Lifetime Opportunity, A |
Elias Ramsberg |
2021 |
English |
Solution, Map |
| One About the Chicken, the Lion and the Monkey?, The |
Sam Barlow |
1998 |
English |
|
| One Girl |
Dr Khel |
2001 |
English |
Solution |
| One Night in the North Atlantic |
Christopher Huang |
1999 |
English |
Map, Solution |
| One Way Out |
Steffen Görzig |
2017 |
English |
|
| Only After Dark |
Gunther Schmidl |
1999 |
English |
Solution, Map |
| OnNoEf |
Evin Robertson |
1999 |
English |
Solution, Map |
| Opening Night |
David Batterham |
2008 |
English |
|
| Order |
John Evans |
2004 |
English |
|
| Orevore Courier |
Brian Rapp |
2007 |
English |
|
| Orion Agenda, The |
Ryan Weisenberger |
2004 |
English |
|
| Orpington |
William J. Shlaer |
1998 |
English |
|
| Oth. |
Gunther Schmidl |
2002 |
English |
Map, Solution |
| Otras Palabras, En |
Aryekaix |
2003 |
Spanish |
|
| Out |
Viktor Sobol |
2019 |
English |
|
| Out Of Line |
Cody Gaisser |
2022 |
English |
|
| Outsided |
Chad Elliott |
1999 |
English |
Solution |