| .X-PNG | The Pixelmator Team | Rasterikuvatiedostot | Portable Network Graphics | Adobe Illustrator CC | Adobe Systems Incorporated |
| .X16 | Macromedia | Datatiedostot | Macromedia Extra Document | Adobe Dreamweaver | Adobe Systems Incorporated |
| .X32 | Adobe Systems Incorporated | Laajennustiedostot | Adobe Xtra File | Adobe Director | Adobe Systems Incorporated |
| .X3F | SIGMA Corporation | Kameran Raakatiedostot | SIGMA X3F Camera RAW File | Adobe Photoshop CC | Adobe Systems Incorporated |
| .XCI | Adobe Systems Incorporated | Asetustiedostot | Adobe Reader Font Mapping File | Adobe Reader | Adobe Systems Incorporated |
| .XDC | Adobe Systems Incorporated | Asetustiedostot | Adobe Acrobat Printer Description | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XDP | Adobe Systems Incorporated | Datatiedostot | XML Data Package | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XFD | JetForm | Datatiedostot | FormFlow 99 Form Data File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XFDF | Adobe Systems Incorporated | Datatiedostot | Adobe Acrobat XFDF File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XFL | Adobe Systems Incorporated | Videotiedostot | Adobe Flash Exchange File | Adobe Animate CC 2017 | Adobe Systems Incorporated |
| .XFT | Cay Horstmann | Fonttitiedostot | ChiWriter Printer Font | Adobe LiveCycle ES4 | Adobe Systems Incorporated |
| .XHTM | Opera Software | Web-tiedostot | Extensible Hypertext Markup Language Document | Adobe Dreamweaver | Adobe Systems Incorporated |
| .XHTML | Opera Software | Web-tiedostot | Extensible Hypertext Markup Language Document | Adobe Dreamweaver | Adobe Systems Incorporated |
| .XMO | Adobe Systems Incorporated | Järjestelmätiedostot | Adobe Authorware Movie Driver | Adobe Authorware | Adobe Systems Incorporated |
| .XMP | Adobe Systems Incorporated | Harvinaiset Tiedostot | Extensible Metadata Platform File | Adobe Photoshop | Adobe Systems Incorporated |
| .XMPSES | Adobe Systems Incorporated | Datatiedostot | Adobe Premiere Elements Data | Adobe Premiere Elements | Adobe Systems Incorporated |
| .XPJ | Adobe Systems Incorporated | Datatiedostot | RoboHelp HTML Project | Adobe RoboHelp | Adobe Systems Incorporated |
| .XPR | Parametric Technology Corporation | 3D-kuvatiedostot | Pro/ENGINEER Part Instance Accelerator File | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XSLT | Syncro Soft | Datatiedostot | XSL Transformation File | Adobe Dreamweaver | Adobe Systems Incorporated |
/1 
