| xport | SAS XPORT Engine Data |
| xpp | Microsoft SQL Server Replication Data |
| xpq | DB/TextWorks Exported Query Screen Definitions |
| xpr | Pro/ENGINEER Part Data |
| xpr | Pro/ENGINEER XPR File |
| xps | DB/TextWorks Exported Set Definitions |
| xps | MonkeyJam Exposure Sheet |
| xpse | KNFB Reader Data |
| xpt | EES Export |
| xpt | SAS XPORT Engine Data |
| xptheme | Theme Manager Theme Package |
| xptin | XPSWMM Hydrology Data |
| xpu | IBM SiteProtector X-press Update File |
| xpw | Accessible FormNet Data File |
| xpx | Accessible FormNet Data File |
| xpy | MarketBrowser Data |
| xqa | PX Windows Board Description Data |
| xqcn | QPST Content |
| xqp | I-Doser Temporary Data |
| xqt | SuperCalc Macro |
| xqx | XQX Printer Stream Data |
| xr | Chaos Desktop Reference File |
| xr2 | Xrecode II Registration Data |
| xr21 | Xrecode II Registration Data |
| xra | SPPAS Annotation Tool Data |
| xrb | GIS Web Template XML Resource Bundle |
| xrb | OpenOffice JAVA Language Translation XML |
| xrb | XMind Resource Bundle |
| xrdml | PANalytical XRD Instruments Data |
| xrds | eXtensible Resource Descriptor Sequence Data |
| xref | IBM AIX Cross Reference Data |
| xresult | Xcode Xresult Data |
| xrf | Cal3D XML Materials Data |
| xrf | IMVU Material File |
| xrff | Weka eXtensible Attribute-Relation File Format Data |
