| 31580 | Conversational French | ZX81 16K | - |
| 31581 | Conversational German | ZX81 16K | - |
| 31582 | Conversational Spanish | ZX81 16K | - |
| 28777 | Conversion | ZX81 16K | English |
| 41322 | Conveyor Belt | ZX81 16K | English |
| 41208 | Copy Function | ZX81 16K | English |
| 40110 | Copycat | ZX81 16K | English |
| 28752 | Coral Basic Interpreter | ZX81 16K | English |
| 28779 | Corner | ZX81 16K | Dutch |
| 39967 | Correlation Coefficient and Regression Analysis | ZX81 16K | English |
| 44859 | Corrida Maluca | ZX81 16K | Portuguese |
| 44156 | Corridors81 | ZX81 16K | English |
| 42446 | Cosmic | ZX81 16K | Portuguese |
| 40999 | Cosmic Dustman | ZX81 16K | English |
| 31583 | Cosmic Guerilla | ZX81 16K | - |
| 41413 | Cosmic Mission | ZX81 16K | English |
| 44181 | Cosmic Payback | ZX81 16K | English |
| 40169 | Costs | ZX81 16K | English |
| 40768 | Cothello | ZX81 16K | English |
| 40016 | Count/Stars | ZX81 16K | English |