Group
- Notting Hill Games/MBI2
- Novus Ordo Seclorum40
- ORC3
- Obatron Productions4
- Obsidian Portal1
- Ohio Men of the Red Chest18
- On The Lamb2
- Onyx Path Publishing4
- Open Design8
- Optimystical Studios6
- Orc Stomp4
- Ottawa Red Shirts48
- Out of the Box Publishing20
- Ozarks Rising23
- P.O.W.E.R. Core Games2
- PM Games3
- Paizo Publishing201
- Palegain Project LLC4
- Pamean Games10
- Pantheon Press4