| 6451 | OPTIMO | 1 |
| 6452 | Optipromo | 1 |
| 6453 | Orange | 1 |
| 6454 | Orange Hat | 1 |
| 6455 | Orange Process | 1 |
| 6456 | OrbitSoft | 1 |
| 6457 | ОрбитСофт | 1 |
| 6458 | Orchid Studio | 1 |
| 6459 | Origami | 1 |
| 6460 | Original Group | 1 |
| 6461 | Orlime Digital | 1 |
| 6462 | ORTA | 1 |
| 6463 | ОСА | 1 |
| 6464 | OscarLab | 1 |
| 6465 | osclass-pro | 1 |
| 6466 | Ошка | 1 |
| 6467 | Осинцев | 1 |
| 6468 | Osk-Market | 1 |
| 6469 | OSMI IT (Ex Осьминожка) | 1 |
| 6470 | Otherwise | 1 |
| 6471 | "Отклик" | 1 |
| 6472 | Открытые ресурсы (г. Киев) | 1 |
| 6473 | ОТМ Россия | 1 |
| 6474 | оура | 1 |
| 6475 | OUT.AGENCY | 1 |
| 6476 | Outreach BRO | 1 |
| 6477 | OVERCLICK | 1 |
| 6478 | OWL agency | 1 |
| 6479 | OWL Agency | 1 |
| 6480 | Oxiv.ru | 1 |
| 6481 | OXY-marketing | 1 |
| 6482 | Oy-li Digital | 1 |
| 6483 | Ozhgibesov.net | 1 |
| 6484 | OZ INTERACTIVE | 1 |
| 6485 | PageFactory | 1 |
| 6486 | PageLab | 1 |
| 6487 | Palex Web | 1 |
| 6488 | Pallada Pro | 1 |
| 6489 | PANAU | 1 |
| 6490 | Panda Ads | 1 |
| 6491 | PANDA Digital Group | 1 |
| 6492 | Panda Moscow | 1 |
| 6493 | Panda-Seo | 1 |
| 6494 | Panda Style | 1 |
| 6495 | Пандаворкс | 1 |
| 6496 | Pandora Research | 1 |
| 6497 | Панеглиф | 1 |
| 6498 | Papaton | 1 |
| 6499 | Папин сайт | 1 |
| 6500 | PARACVET | 1 |
