| xad | eXotic ADlib Audio |
| xfs | eRacer Sound |
| xgc | Binary eXtended Genesis Music |
| xgm | eXtended Genesis Music |
| xi | FastTracker 2 Instrument |
| xiz | ZynAddSubFX Instrument File |
| xkr | Sing-Magic Karaoke Song |
| xm | FastTracker 2 Music Module |
| xma | Xbox 360 Native Audio |
| xmf | Extensible Music Format File |
| xmf0 | Extensible Music Format File |
| xmf1 | Extensible Music Format File |
| xmi | Extended MIDI Song |
| xms | XMS Tracker Module |
| xmz | ZynAddSubFX Master File |
| xmz | FastTracker 2 Extended Module |
| xp | FastTracker 2 Pattern |
| xrns | Renoise Song |
| xsb | XACT Sound Bank |
| xspf | XML Shareable Playlist File |
| xt | Fast Tracker 2 Music Track |
| xt | Fastracker 2 Track |
| xvag | Sony PlayStation 3 Audio File |
| xwb | XACT Wave Bank |
| ym | Atari ST Audio Data |
| 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 |
