- Oared Vessels
- Oath of Fealty
- Oaths
- Observe Animal Fetus
- Observe Human Fetus
- Occultatum Aspectum
- Ockhill
- October
- Odyl
- Off With You
- Oil Lamp
- Old Anglia
- Old Church
- Old Empire
- Old Gods
- Old Souls
- Old Ways
- On Brimian Aspect
- One score
- On the morrow
- Open Organization
- Orange Tree Island
- Order of Doves
- Order of Inquiry
- Order of Letters
- Order of Mercy
- Order of Ministry
- Order of Outreach
- Order of Shadowknights
- Order of St. Epictetus
- Order of St. Posidonius
- Order of St. Seneca
- Order of the Old Gods
- Order of Vigilants
- Organization of Armies
- Orientation
- Orientation String
- Original State
- Orlow Codington
- Ormaz
- Osbert Middlewick
- Osric Hemel Ashbolt
- Otherworld
- Otters
- Otterwich
- Otterwich Ambrosia
- Ounce
- Our Cherished Saints
- Ouroboros
- Outer Empire
- Out of the Game
- Outrage
- Ox
- Oy
- Oyez
