O

Obelevenebration
Observe, young Jedi!
occult
Obvious Door Spell
OGL
Oh my God, they killed Kenny!
old school WoD
olympic turns
omnigamer
one-off game
One Ring, The
one-sided die
Onyx Path Publishing
OOC
OOGA
OOM
open-ended rolling
option X
orc
Orcish Healing
OrNME
otaku
owlbear
own, to