Document

Markup

 * HTML (HyperText Markup Language)
 * Markdown
 * SGML (Standard Generalised Markup Format)
 * TEI (Text Encoding Initiative; Specialised dialect of SGML)
 * TEX (TeX)
 * XHTML (Extensible HTML)
 * XML

Presentation

 * ODP (OpenDocument presentation)
 * PPT (PowerPoint presentation)
 * PPTX (PowerPoint presentation, XML format)
 * SXI (StarOffice)

Spreadsheet

 * Lotus 1-2-3
 * Lotus Symphony
 * ODS (OpenDocument spreadsheet)
 * SDC (StarOffice spreadsheet)
 * XLS (Excel spreadsheet format)
 * XLSX (Excel spreadsheet format, XML version)
 * SuperCalc 3
 * Visicalc

Word Processor

 * ABW (Abiword word processor)
 * CHI (ChiWriter word processor)
 * DOC (Word document)
 * DOCX (Word document, XML format)
 * DOT (Word template)
 * DOTX (Word template, XML format)
 * EasiWriter (Word processor file format)
 * MultiMate Professional Word Processor
 * ODT
 * OTT
 * SXW StarOffice?
 * Wordstar
 * Wordstar 2000

Other

 * 602
 * ACL
 * AFP
 * ANS
 * ASC
 * AWW
 * AZW
 * CCF
 * CSV
 * CWK
 * DJVU
 * DOX (Mutimate document, and others)
 * EGT
 * EPUB
 * FDX
 * FTM
 * FTX
 * GM6 (Game Maker 6 source)
 * GMK (Game Maker 7-8 source)
 * HWP
 * HWPML
 * Impression (Desktop Publishing file format)
 * LWP
 * MBP
 * MCW
 * MOBI
 * NB
 * NBP
 * ODM
 * OMM
 * PAGES
 * PAP
 * PAT (Multimate document, and many others)
 * PDAX
 * PDF (Portable Document Format)
 * QUOX
 * RTF (Rich Text Format)
 * RTFD (Rich Text Format Directory)
 * RPT
 * scriv (Scrivener document format)
 * SDW
 * STW
 * SXW
 * TechWriter (Scientific word processor file format)
 * TXT (Un-structured text document)
 * UOF
 * UOML
 * VIA
 * WPD
 * WPS
 * WPT
 * WRD
 * WRF
 * WRI
 * XPS