| 26898 | Instant Command | ZX-Spectrum 16K | English |
| 16557 | Interrupcion No Enmascarable | ZX-Spectrum 48K | Spanish |
| 30005 | JOY | ZX-Spectrum 48K | English |
| 26483 | Joystick Control | ZX-Spectrum 48K | Italian |
| 25100 | Karel | ZX-Spectrum 48K | Czech |
| 35542 | Karel | ZX81 16K | Czech |
| 2675 | Karel 85 | ZX-Spectrum 48K | Czech |
| 22896 | KeyUsr | ZX-Spectrum 48K | English |
| 23217 | Keypress | ZX-Spectrum 48K | English |
| 22100 | Kwikwrite | ZX-Spectrum 48K | English |
| 20318 | LISP | ZX-Spectrum 48K | English |
| 8718 | LISP Interpreter | ZX-Spectrum 48K | English |
| 17740 | LOGO | ZX-Spectrum 48K | Portuguese |
| 41839 | Lattice C | Sinclair QL | - |
| 21961 | Linedit | ZX-Spectrum 48K | English |
| 41840 | Lisp Development Ki | Sinclair QL | - |
| 29039 | List Scroll | ZX81 2K | English |
| 37473 | Listador BASIC | ZX-Spectrum 48K/128K | Spanish |
| 38053 | Listador BASIC para Plus-3 | ZX-Spectrum 128 +3 | Spanish |
| 16748 | Listvars | ZX-Spectrum 16K | English |