daddypa
Obi Wan Kenobi
Obie (O.B.)
Obijuan
Obo
Obsidian
Obsididan
Obstinate
Ocabar
Occi
Occupant
Ocelot
Oci Osborne
Ocitar
Octavia
October
Odan
Odd
Oddball
Oddibe
Oddly McStrange
Odeipus
Odessa
Odette
Odie
Odile
Odin (Viking mythology: the allmighty god)
Odo
Odyssey
Oedipus
Ofel