| Extension | Information |
| !C | Graphics Converter Pro |
| ### | DoubleSpace Compressed Volume |
| ### | QTIC Temporary File |
| ### | Temporary File |
| #01 | Numbered Picture Files |
| #24 | Locoscript 24-pin Printer Data File (LocoScript Software) |
| #GF | MetaFont Font File |
| #IB | Locoscript Dot Matrix Data File (LocoScript Software) |
| #SC | Locoscript Dot Matrix Data File (LocoScript Software) |
| #ST | Locoscript Dot Matrix Printer Definition File (LocoScript Software) |
| $ | BASIC VB VB1D Komp Symbole File |
| $#! | AOL 5.0 Virchk File (America Online, Inc.) |
| $#! | Cryptext |
| $$$ | Backup |
| $$$ | Temporary File |
| $$$ | Used by OS/2 to keep track of archived files |
| $$A | OS/2 (IBM) |
| $$F | OS/2 Database (IBM) |
| $$P | OS/2 Notes (IBM) |
| $$S | OS/2 Spreadsheet (IBM) |
| $$_ | Midiprg Capella Compressed File |
| $00 | DOS Pipe File |
| $01 | DOS Pipe File |
| $01 | Midi File |
| $02 | DOS Pipe File |
| $02 | Midi File |
| $03 | DOS Pipe File |
| $04 | DOS Pipe File |
| $05 | DOS Pipe File |
| $1 | ZX Spectrum-Emulator |
| $A | AutoCAD Autosave File (Autodesk, Inc.) |
| $AC | AutoCAD Autosave File (Autodesk, Inc.) |
| $AC | $&Sense Data File (Monogram Software/Software Toolworks/The Learning Company) |
| $B5 | Apple II ProDOS 16 or GS/OS Shell Application (Apple Computer, Inc.) |
| $C | Graphics Converter Pro |
| $D$ | OS/2 Planner Data File |
| $DB | dBASE Temp File |
| $DX | Ca Visual Objects Platform for Developer (CAVO) Backup Index File (CA) |
| $ED | C Editor Temporary File (Microsoft) |
| $ED | C/C++ Temporary Editor File (Microsoft) |
| $EU | Midiprg Mustat Compressed File |
| $ID | Cubase Compressed File (Steinberg) |
| $LL | Cubase Compressed File (Steinberg) |
| $LN | C++ TLink Response File (Borland Software Corporation) |
| $NG | Midiprg Mustat Compressed File |
| $OL | DOS Pipe File |
| $ON | Cubase Fonts Compressed File (Steinberg) |
| $RI | Cubase Audio Compressed File (Steinberg) |
| $RR | Cubase Compressed File (Steinberg) |
| $S | Graphics Converter Pro |
| $TF | Cubase Fonts Compressed File (Steinberg) |
| $VM | Windows 3.x Virtual Manager Temp File (Microsoft) |
| $WM | Epson Creative Studio Example File |
| $XE | Mustat Compressed Audio File |
| &&& | Temporary File |
| (D) | pcAnywhere Temporary File |
| )2( | LHA Archiver Temporary File |
| --- | Microsoft Backup File Set (Microsoft) |
| --- | Windows Temporary File |
| -5 | Audio Utility Tuningwrench Compressed File |
| .DAT | Clarion DOS Database (SoftVelocity) |
| ??? | ANY Three Character Audio File |
| ??? | Trend Micro Virus Pattern File (Trend Micro, Inc.) |
| ??_ | InstallShield Compressed File (InstallShield Software Corporation) |
| ??_ | Microsoft KWAJ compressed (Phil Katz's 'deflate') |
| ??_ | Microsoft SZDD compressed (Haruhiko Okumura's LZSS) |
| @@@ | Screen Files |
| @HA | ImsiSoft E-mail Animator |
| [B] | Amiga Paint File (Amiga) |
| _00 | Soundtrack Compressed File |
| _01 | Soundtrack Compressed File |
| _02 | Soundtrack Compressed File |
| _1 | Audio Utility Tuningwrench Compressed File |
| _2 | Audio Utility Tuningwrench Compressed File |
| _3 | Audio Utility Tuningwrench Compressed File |
| _8 | Audio Utility Tuningwrench Compressed File |
| _DB | Stratum Data Icons File |
| _DD | Norton Disk Doctor Recovered File |
| _DL | Form of DLL File |
| _DM | Nuts n Bolts Disk Minder Recovered File |
| _EX | Form of EXE File |
| _H | Type Manager Japanese Font Outline (Adobe) |
| _MP | InstallShield Temporary Installer File (InstallShield Software Corporation) |
| _NT | Form of NT File |
| _RS | RVS-COM Service Pack (Living Byte Software GmbH) |
| _SY | Form of SYS File |
| _V | Type Manager Japanese Font Metrics (Adobe) |
| _VX | Form of VXD File |
| __INCOMPLETE___ | WinMX Incomplete Download (Frontcode Technologies) |
| ___ | Adinf table |
| ___FPE | Folder Password Expert Protected Folder (ZQS Software Team) |
| {PB | Backup |
| ~ | Temporary File |
| ~$~ | 1st Reader Temporary File |
| ~01 | (~01..~99) Norton Editor Backup File |
| ~1~ | Illum Source File |
| ~AP | C++ AppExpert Project Database File (Borland Software Corporation) |
| ~BM | Img RC File |
| ~CU | Cursor File |
| ~DE | C++ Project Backup File (Borland Software Corporation) |
| ~DF | Delphi DFM File Backup (Borland Software Corporation) |
| ~DFM | Delphi Backup File (Borland Software Corporation) |
| ~DP | Delphi DPR File Backup (Borland Software Corporation) |
| ~DR | ARKEY Drawing Backup |
| ~MN | Norton Commander Menu Backup |
| ~NT | NT Install Files |
| ~NT | XP Install File |
| ~PA | Delphi PAS File Backup (Borland Software Corporation) |
| ~PAS | Delphi Backup (Borland Software Corporation) |
| ~PR | Terramodel Project Backup |
| ~RE | Image File |
| ~SG | TAPCIS Message Index File |
| ~T~ | RK Archiver Temporary File (RK Software) |
| ~_~ | Temporary File (Microsoft) |
| ~~A | Ap File |
| ~~D | Windows Applog File |
| ~~F | Windows Applog File |
| ~~M | Windows Applog File |
| ~~~ | Temporary file |