| hss | Adobe Photoshop Hue/Saturation Data |
| hst | 3DCS Analysis Histogram Data |
| hst | Corel WordPerfect Office History Data |
| hst | General History File |
| hst | Netscape Navigator History Data |
| hst | Yahoo! Messenger History Data |
| hstx | Altair HyperStudy Package |
| hsw | STEPS Frequency Response Data |
| hsz | Handyscript Skin |
| ht1 | Google Desktop HT1 File |
| hta | S10 WebAlbums Data |
| htb | Audacity Help File |
| hte | HealthStream Express Exported Test Data |
| htf | Hydrographic Transfer Format Data |
| htheme | Thinkfree Office NEO Show Theme |
| hti | MXKEY HTI Data |
| htk | HTK Format Parameter File |
| htmenx | Egis Encrypted HTML Data |
| htmsql | SAS/IntrNet htmSQL Data |
| htn | Micrografx Picture Publisher 8 Print Style Data |
| hto | Survex Hierarchical Tagged Objects File |
| htp | Autodesk AutoCAD Civil 3D Slope Template Definition |
| htpasswd | Apache Password File |
| htpl | IBM Rational Application Developer WebContent Theme |
| htr | Motion Analysis Skeletal Data |
| htrc | HTRC Workset Toolkit Configuration Data |
| htri | HTRI Xchanger Suite Data Input |
| hts | HyperTuner Skin |
| hts | MetaTrader Historical Data |
| hts | Steam Client Saved Game Data |
| htv | HTV Teletekst Data |
| htw | Webhits Template |
| htx | Microsoft Frontpage Database Results Data |
| hub | Lattice Reveal Analyzer HUB Data |
| hud | HUD Maker File |
