O
| Oase | Olanda | Onaka | Orno |
| Obelix | Olando | Ondra | Orphan |
| Ober | Olandra | Ondy | Orpheus |
| Oby | Olav | One | Orpie |
| Oby | Olax | Onex | Orsa |
| Ocean | Olda | Onie | Orscha |
| Ocki | Oldi | Onja | Orsen |
| Octavia | Oldie | Onno | Orsina |
| Octavio | Oldo | Onsa | Orta |
| Oda | Ole | Onzo | Orte |
| Odal | Oleanda | Opal | Ortega |
| Odana | Olena | Ophelia | Ortila |
| Oddi | Oletta | Opus | Orville |
| Odemis | Olex | Ora | Osborn |
| Odeo | Olexa | Oraine | Osca |
| Odessa | Olga | Oran | Oscar |
| Odet | Olida | Orana | Oscha |
| Odeth | Olievia | Oraya | Oschi |
| Odette | Olina | Orbi | Oska |
| Odi | Olinda | Orbit | Oskar |
| Odie | Olinde | Orby | Oslo |
| Odila | Olira | Orca | Osra |
| Odilia | Olita | Orchidee | Oss |
| Odin | Oliva | Orco | Osta |
| Odina | Olive | Ordo | Ostara |
| Odine | Oliver | Orella | Ostara |
| Odion | Olivia | Orena | Ostia |
| Ody | Olivier | Orga | Ostra |
| Odyssey | Olja | Organ | Otella |
| Oeki | Olle | Oria | Othello |
| Oescha | Ollie | Oriana | Otis |
| Ofra | Olliver | Orie | Otte |
| Ogar | Olly | Orina | Otter |
| Ogotha | Olm | Oriolo | Ottessa |
| Ohara | Olmar | Orion | Ottie |
| Ohio | Olona | Orissa | Ottilia |
| Ohla | Olsa | Orka | Ottis |
| Ohra | Olsen | Orkan | Otto |
| Oj | Olympia | Orko | Otty |
| Okar | Olympius | Orla | Ouzie |
| Okay | Oma | Orlan | Ouzo |
| Oki | Omar | Orlanda | Over |
| Okie | Omara | Orlando | Oxana |
| Okki | Omega | Orlinda | Oz |
| Okky | Omer | Orly | Ozean |
| Oktavia | Omera | Orma | Ozon |
| Ola | Omero | Orna | Ozzie |
| Olaf | Ona | Ornella | Ozzy |