| Abbreviation | Definition |
|---|---|
| YBM | Face file Bitmap graphics |
| YC | YACC Archive |
| YDO | Yarston Text Editor Text Document |
| YIF | Color with lookup table Graphics |
| YML | Sailfish Yacht Analyzer XML-based Data File |
| YMP | MicroSim PCBoard Mapping File |
| YN | Audio Utility Tuningwrench Compressed File |
| YNC | yEnc Encoded File |
| YNX | Seqmax Seqprest Compressed Audio File |
| YUV | Abekas YUV file Bitmap graphics |
| YUV3 | CCIR 601 2:1:1 file Bitmap graphics |
| YYC | Wave Sapphire Distribution File |
| YZ | YAC Compressed file archive |
| YZ1 | DeepFreezer Compressed Archive file |
| Z | Compressed file archive.Z |
| Z | Unix Compressed file archive.z (binary) |
| Z# | Frotz Z-Code Game |
| Z1 | ZoneAlarm File |
| Z3 | Infocom game module |
| Z80 | ZX Spectrum emulator Snapshot |