.ha - Compressed file archive created by HA.

.ham - Electronic Arts DeluxePaint. Picture indexes and sound files used in 3D games.

.hdf - Heirarchical Data Format. Object-oriented interchange file format used to transport image data from one machine architecture or operating system to another with no adverse effects. ( filename extension )

.hlb - Help Library file for use on a VMS system.

.hlp - Help file format. Standard used with Windows Help files. ( filename extension )

.hpk - Compressed file archive created by HPAK.

.hqx - Compressed Macintosh ASCII archive format created by BinHex. Translates Macintosh files into text for transfer purposes.

.hrf - Hitachi Raster Format. Used to store scanner output data.

.htm, .html - Hypertext Markup Language file format. Used for creating and viewing Web pages. ( filename extension )

.hyp - Compressed file archive created by HYPER. ( filename extension )

.hz - Hanzi format. A data format for exchanging files of arbitrarily mixed Chinese and ASCII characters.