Group
- Northern Ohio Wargaming Society6
- Northern Virginia Gamers (NOVAG)18
- Not Just Another Gaming Podcast1
- Novus Ordo Seclorum75
- ODAM Publishing4
- ONE SHOT Podcast Network25
- Oathbreaker Games6
- Octoraffe Games11
- Off the Page Games1
- Offcut Games21
- Ohio Kimono, LLC4
- Old Curmudgeon Studios6
- Old Gamers Group3
- Old School Publish Presents ACKS1
- Onyx Path Publishing4
- Onyx Path Publishing 59
- Open for Adventure1
- Orc Stomp1
- Orc Stomp 5K Fun Run1
- Orcs Unlimited Games27