| .X13 | DarXabre | File di giochi | Hooligans Game Archive File | Dragon UnPACKer | Open Source |
| .XA2 | Csabo | File di giochi | XWE Data File | XWE | Open Source |
| .XAC | Tilted Mill Entertainment | File di giochi | SimCity Societies Game File | SimCity Societies | Tilted Mill Entertainment |
| .XAN | Team17 | File di giochi | Worms Map File | Team17 Worms Mayhem | Team17 |
| .XCR | Strategic Studies Group | File di giochi | Warlords Battlecry Game File | Warlords Battlecry | Strategic Studies Group |
| .XDP | Adobe Systems Incorporated | File di giochi | XML Data Package | Adobe Acrobat DC | Adobe Systems Incorporated |
| .XDS | Nintendo | File di giochi | DS Game Maker Project File | Invisionsoft DS Game Maker | Nintendo |
| .XEN | Activision | File di giochi | Guitar Hero 3 Data File | Guitar Hero 3 | Neversoft |
| .XEX | Microsoft Corporation | File di giochi | Xbox 360 Executable File | Microsoft XBOX | Microsoft Corporation |
| .XMB | Microsoft Corporation | File di giochi | Age Of Empires Game Data File | Microsoft Age of Empires | Ensemble Studios |
| .XNB | Microsoft Corporation | File di giochi | XNA Game Studio Binary Package | Microsoft XNA Game Studio | Microsoft Corporation |
| .XOF | Themekit Systems Ltd | File di giochi | Reality Lab 3D Image File | MindRender Virtual Reality Explorer Kit | Themekit Systems Ltd |
| .XOM | Team17 | File di giochi | Worms 3D Object File | Team17 Worms Mayhem | Team17 |
| .XP | Starbreeze Studios | File di giochi | Fastracker 2 Pattern | Fasttracker | Starbreeze Studios |
| .XP3 | Open Source | File di giochi | KiriKiri Package File | XP3 / Kirikiri tools | Open Source |
| .XPC | Codejunkies | File di giochi | DSI Action Replay Saved Code | DSi Action Replay | Codejunkies |
| .XPD | Sony | File di giochi | PlayStation Store PSP License File | PlayStation | Sony |
| .XPK | THQ Nordic | File di giochi | WWE RAW Model File | Cygnus Hex Editor | SoftCircuits |
| .XPX | Intercon Associates | File di giochi | Intercon FormNet File | Accessible FormNet | Intercon Associates |
| .XRD | D. G. Jones and A. K. Dewdney | File di giochi | Core Wars Data | Core War | D. G. Jones and A. K. Dewdney |
| .XS | Microsoft Corporation | File di giochi | Age Of Empires 3 Map AI Generator | Microsoft Age of Empires | Ensemble Studios |
| .XTBL | Unknown Developer | File di giochi | XTBL Ransomware Encrypted File | AVG Antivirus | AVG Technologies |
| .XXI | IGN Entertainment | File di giochi | GameSpy Arcade Game File | GameSpy Arcade | IGN Entertainment |
| .XXW | Pandemic Studios | File di giochi | Zero Engine Terrain Data | Star War: The Clone Wars | LucasArts Entertainment Company, LLC |
| .XXX | BloodDolly | File di giochi | TeslaCrypt 3.0 Ransomware Encrypted File | Tesla Decoder | BloodDolly |
di 1 
