| .H! | Perfect world Inc. | Tietokantatiedostot | Perfect Database Help Database File | Unknown Software | Unknown Developer |
| .H1 | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HAI | Unknown Developer | Harvinaiset Tiedostot | Ntgraph Nt09b-2b Emx Lib File | Unknown Software | Unknown Developer |
| .HARP | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HBQ | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HEAD | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HEADER | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HEB | Unknown Developer | 3D-kuvatiedostot | DEcomp 3D Scene Data | DEcomp | Unknown Developer |
| .HEC | Unknown Developer | Datatiedostot | Grafic Pvquan Quant File | Unknown Software | Unknown Developer |
| .HED | XnSoft | Graafiset Tiedostot | Hi-Eddi Image File | Unknown Software | Unknown Developer |
| .HELPER | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HER | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HEY | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HFI | Hewlett-Packard | Fonttitiedostot | HP Font | Unknown Software | Unknown Developer |
| .HFX | Smith Micro Software | Datatiedostot | HotFax Data File | Unknown Software | Unknown Developer |
| .HGC | Unknown Developer | Datatiedostot | PC Fold Data | PC Fold | Unknown Developer |
| .HIGH | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HJD | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HLF | Eugene Roshal | Datatiedostot | FAR Manager Help Data | Hires Interlaced | Unknown Developer |
| .HLG | BMERC | Datatiedostot | BMERC Homolog File Format | Unknown Software | Unknown Developer |
| .HLT | Unknown Developer | Datatiedostot | Watcher Database Trades List File | Watcher Database | Unknown Developer |
| .HLW | Unknown Developer | Datatiedostot | Win32/AMalum.EDHZ Data | Unknown Software | Unknown Developer |
| .HM4 | Lorex Technology | Varmuuskopiointitiedostot | Lorex Backup File | Unknown Software | Unknown Developer |
| .HNB | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HNL | Unknown Developer | Datatiedostot | Hunter MFC Data | Unknown Software | Unknown Developer |
| .HNM | Cryo Interactive Entertainment | Videotiedostot | Cryo HNM Movie Soundtrack | Unknown Software | Unknown Developer |
| .HNQ | Unknown Developer | Harvinaiset Tiedostot | Hunter File | Unknown Software | Unknown Developer |
| .HNT | Unknown Developer | Harvinaiset Tiedostot | Hunter CSV Based Collections | Unknown Software | Unknown Developer |
| .HNY | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HOF | Unknown Developer | Pelitiedostot | Hall Of Fame Data | Unknown Software | Unknown Developer |
| .HONMOD | S2 Games | Pelitiedostot | Heroes Of Newerth (HON) Modification Manager File | HON Modification Manager | Unknown Developer |
| .HOR | Unknown Developer | Datatiedostot | Horoscope Data | Winhoro | Unknown Developer |
| .HOX | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HP5 | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HP?= | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HPDATA | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HPF | IBM | Sovelluskehittäjän tiedostot | High Performance Fortran File | Fortran 90 With The pghpf Extension | Unknown Developer |
| .HPH | Unknown Developer | Harvinaiset Tiedostot | Designer Graphics System 2 Data File | Designer Graphics System 2 | Unknown Developer |
| .HPI | Hemera Technologies | Rasterikuvatiedostot | Hemera Photo Objects Image File | HEMERA software | Unknown Developer |
| .HPRT | Apple | Datatiedostot | Golden Orchard Apple II CD Rom File | Unknown Software | Unknown Developer |
| .HQB | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HQM | Unknown Developer | Pelitiedostot | Hardcore Questing Mode Data File | Hardcore Questing Mode | Unknown Developer |
| .HR | Atari Corporation | Graafiset Tiedostot | Atari Picture Image File | Unknown Software | Unknown Developer |
| .HRYX | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HSM | Unknown Developer | Sovelluskehittäjän tiedostot | Assembly Language Header File | Assembly Programming Language | Unknown Developer |
| .HUA | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HUF | David A. Huffman | Datatiedostot | Huffman Encoded Data | Unknown Software | Unknown Developer |
| .HVL | Unknown Developer | Äänitiedostot | Commodore Amiga HivelyTracker Audio Module | Hively Tracker | Unknown Developer |
| .HVT | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HVUF | Unknown Developer | Datatiedostot | Hydraulic Calculation Format | Unknown Software | Unknown Developer |
| .HWA | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HWK | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HX_ | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HYB | Unknown Developer | Harvinaiset Tiedostot | Uncommon File Extension | Unknown Software | Unknown Developer |
| .HYD | MARIN | Tietokantatiedostot | MARIN Hydrodynamic Database File | Unknown Software | Unknown Developer |
| .HYL | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
| .HZ | Unknown Developer | Tekstitiedostot | Chinese (Hanzi) Text | Unknown Software | Unknown Developer |
| .HZB | Unknown Developer | Harvinaiset Tiedostot | Unknown File Type | Unknown Software | Unknown Developer |
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