| xsml | iRomplerMap Audio Data |
| xspf | XML Shareable Playlist File |
| xt | Fast Tracker 2 Music Track |
| xvag | Sony PlayStation 3 Audio File |
| xwb | XACT Wave Bank |
| xwm | Microsoft xWMA Compressed Audio |
| xwma | Microsoft xWMA Compressed Audio |
| xwv | Valve Xbox360 Audio Data |
| yadpcm | Yamaha 4-bit ADPCM Format RAW Data |
| ym | Atari ST Audio Data |
| ynx | Seqmax Seqprest Compressed Audio |
| ytif | Yellow Tools Independence Image |
| ytil | Yellow Tools Independence Instrument Library |
| z00 | Casio WK-3000 Rythm Data |
| zab | Zipped Audio Book |
| zaf | Zoom Recorded Audio |
| zax | Zaxcom Audio Data |
| zdv | Zyxel Voice Mail Audio Data |
| zgr | Zero-X BeatCreator Loop |
| zmon | Commodore Amiga ZoundMonitor Audio Module |
| zvd | Zyxel Modem Voice Data |
| zvr | SAFA Voice Recorder Data |
| zxs | ZX Music Player Sound |
| zyx | Zyxel Voice Mail Audio Data |