| hru | SWAT HRU Data |
| hrv | HRVTool Data |
| hrz | Poser Compressed Hair Data |
| hs2 | HyperRESEARCH 2 Study |
| hs3 | HyperRESEARCH 3 Study |
| hs6lic | HyperSnap License Data |
| hs7lic | HyperSnap License Data |
| hsa | Hagaki Studio Address Book |
| hsc | Aspen HYSYS Simulation |
| hscx | HemoSpat Coordinate Exchange Format Data |
| hsh | Microsoft Surface Calibration Hash |
| hsh | Microsoft IIS Metabase Hash File |
| hsh | Microsoft Windows Catalog Search Index Hash |
| hsk | Nimbus 7 SAMS HSK Data |
| hsn | HostScan Hosts Data |
| hsp | iGO Primo Histspeed File |
| hsr | RezeptAssist Exported Data |
| hss | Adobe Photoshop Hue/Saturation Data |
| hst | General History File |
| hstx | Altair HyperStudy Package |
| hsw | STEPS Frequency Response Data |
| ht1 | Google Desktop HT1 File |
| hta | S10 WebAlbums Data |
| htb | Audacity Help File |
| htf | Hydrographic Transfer Format Data |
| htheme | Thinkfree Office NEO Show Theme |
| hti | MXKEY HTI Data |
| htk | HTK Format Parameter File |
| htn | Micrografx Picture Publisher 8 Print Style Data |
| hto | Survex Hierarchical Tagged Objects File |
| htpasswd | Apache Password File |
| htpl | IBM Rational Application Developer WebContent Theme |
| htri | HTRI Xchanger Suite Data Input file |
| hts | HyperTuner Skin |
| htv | HTV Teletekst Data |