| ID | Name | Type |
|---|---|---|
| #2615 | Clown | ? |
| #2616 | Club Software | Z |
| #22769 | Club de Aventuras AD (CAAD) | P |
| #20247 | Clube Nacional de Aventura | P |
| #2617 | Clwyd Adventure Software | Z |
| #17143 | Clwyd Personal Computers | H |
| #2618 | Clyde W. Bish | + |
| #21794 | Cláudio Costa | + |
| #21707 | Cláudio Graça | + |
| #19599 | Cláudio José Costa | + |
| #21953 | Cláudio de Freitas B. Bittencourt | + |
| #20985 | CnP Projectz | P |
| #2619 | CoMAD Soft | Z |
| #18902 | Coalheart | - |
| #17144 | Cobolt Systems | I |
| #2620 | Cobra | ? |
| #2621 | Cobra Computer Software | Z |
| #20525 | Cobra Laser | P |
| #2622 | Cobra Soft [FR] | Z |
| #2623 | Cobra Soft [UA] | Z |