| .T | Holt Software | Arquivos de dados | Turing Source Code File | Holt Software Turing | Holt Software |
| .T01 | H&R Block | Arquivos de dados | TaxCut 2001 File | H&R Block TaxCut 2001 | H&R Block |
| .T02 | H&R Block | Arquivos de dados | TaxCut 2002 File | H&R Block TaxCut 2002 | H&R Block |
| .T03 | H&R Block | Arquivos de dados | TaxCut 2003 File | H&R Block TaxCut 2003 | H&R Block |
| .T05 | H&R Block | Arquivos de dados | TaxCut 2005 Tax Return Data | TaxCut 2006 | H&R Block |
| .T06 | H&R Block | Arquivos de dados | TaxCut 2006 Tax Return File | TaxCut 2006 | H&R Block |
| .T10 | H&R Block | Arquivos de dados | At Home 2010 Tax Return | H&R Block Tax Software | H&R Block |
| .T2 | RM Education | Arquivos de dados | Textease 2000 File | Textease 2000 | RM Education |
| .T2K | Basement.nl | Arquivos de dados | Teach2000 Document | Teach2000 | Basement.nl |
| .T2KS | Basement.nl | Arquivos de dados | Teach2000 Exam Results File | Teach2000 | Basement.nl |
| .T2KT | Basement.nl | Arquivos de dados | Teach2000 Exam File | Teach2000 | Basement.nl |
| .T2L | Elevenworks LLC | Arquivos de dados | TouchDraw Library | TouchDraw | Elevenworks LLC |
| .T32 | Symantec Corporation | Arquivos de dados | Drive Image 5 File | PowerQuest Drive Image | Symantec Corporation |
| .T99 | H&R Block | Arquivos de dados | TaxCut Data File | TaxCut 2006 | H&R Block |
| .TA0 | TaxAct | Arquivos de dados | TaxAct 2014 Tax Return File | TaxAct | TaxAct |
| .TA1 | TaxAct | Arquivos de dados | TaxACT 2001 Tax Form File | TaxAct | TaxAct |
| .TA2 | TaxAct | Arquivos de dados | TaxAct 2014 Tax Return File | TaxAct | TaxAct |
| .TA3 | TaxAct | Arquivos de dados | TaxAct 2014 Tax Return File | TaxAct | TaxAct |
| .TA4 | TaxAct | Arquivos de dados | TaxAct 2014 Tax Return File | TaxAct | TaxAct |
| .TA5 | TaxAct | Arquivos de dados | TaxAct 2015 Tax Return File | TaxAct | TaxAct |
| .TAB | Microsoft Corporation | Arquivos de dados | Tab Separated Data File | Microsoft Excel | Microsoft Corporation |
| .TABLE1 | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TABLES | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TAC | Parmerlee, Inc. | Arquivos de dados | ActiCalc Data File | ActiCalc | Parmerlee, Inc. |
| .TAG | Data Access Worldwide | Arquivos de dados | DataFlex Data File | DataFlex | Data Access Worldwide |
| .TAH | Borland | Arquivos de dados | Turbo Assembler Help Data File | Turbo Assembler | Borland |
| .TAI | NVIDIA | Arquivos de dados | NVIDIA Texture Atlas Creation Tool Texture Data | Texture Atlas Tools | NVIDIA |
| .TAL | Adobe Systems Incorporated | Arquivos de dados | Adobe TypeAlign Text Illustration File | Adobe TypeAlign | Adobe Systems Incorporated |
| .TALK | Unknown Developer | Arquivos de dados | Text To Speech File | Unknown Software | Unknown Developer |
| .TALK2 | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TAR | Jean-loup Gailly and Mark Adler | Arquivos de dados | Consolidated Unix File Archive | 7-Zip | Igor Pavlov |
| .TASK | Hewlett-Packard | Arquivos de dados | HP Printer Utility Task Plugin File | HP Printer Utility (for Mac) | Hewlett-Packard |
| .TAX | Intuit, Inc. | Arquivos de dados | TurboTax Tax Return | Intuit Quicken | Quicken |
| .TAX2008 | Intuit, Inc. | Arquivos de dados | TurboTax 2008 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2009 | Intuit, Inc. | Arquivos de dados | TurboTax 2009 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2010 | Intuit, Inc. | Arquivos de dados | TurboTax 2010 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2011 | Intuit, Inc. | Arquivos de dados | TurboTax 2011 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2012 | Intuit, Inc. | Arquivos de dados | TurboTax 2012 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2013 | Intuit, Inc. | Arquivos de dados | TurboTax 2013 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2015 | Intuit, Inc. | Arquivos de dados | TurboTax 2015 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TAX2016 | Intuit, Inc. | Arquivos de dados | TurboTax 2016 Tax Return | Intuit TurboTax | Intuit, Inc. |
| .TB | Tabbery | Arquivos de dados | Tabbery Tab File | Tabbery | Tabbery |
| .TB3 | Intel Corporation | Arquivos de dados | Intel VTune Performance Monitor File | Intel VTune | Intel Corporation |
| .TBA | Inmagic | Arquivos de dados | DB/Text Database Primary Textbase Definition File | DB/TextWorks | Inmagic |
| .TBB | Microsoft Corporation | Arquivos de dados | Microsoft Office Toolbar Button | Microsoft Office | Microsoft Corporation |
| .TBC | Psygnosis | Arquivos de dados | Formula One 2001 Season 01 Vehicles Data | Formula One 2001 | Psygnosis |
| .TBF | Trellian Software | Arquivos de dados | Trellian Button Factory File | Trellian Button Factory | Trellian Software |
| .TBH | PowerBASIC, Inc. | Arquivos de dados | Turbo Basic Help File | PowerBASIC | PowerBASIC, Inc. |
| .TBI | Electronic Arts | Arquivos de dados | FIFA 2001 Game Data | FIFA 2001 | EA Sports |
| .TBK | SumTotal Systems | Arquivos de dados | ToolBook Project File | ToolBook | SumTotal Systems |
| .TBL | Blizzard Entertainment Inc. | Arquivos de dados | StarCraft Information Table | StarCraft | Blizzard Entertainment Inc. |
| .TBT | ARRIS | Arquivos de dados | Timbuktu Pro Remote Control Software File Format | Timbuktu | ARRIS |
| .TBV | Brain Innovation | Arquivos de dados | Turbo-BrainVoyager Data File | Turbo-BrainVoyager | Brain Innovation |
| .TBX | Simple DirectMedia Layer (SDL) | Arquivos de dados | SDL Trados Studio Glossary Data | Sublime Text | Sublime HQ Pty Ltd |
| .TC | TrueCrypt | Arquivos de dados | TrueCrypt Volume | TrueCrypt | TrueCrypt |
| .TCC | Pro Systems | Arquivos de dados | TimeCalc Classic Data File | TimeCalc Classic | Pro Systems |
| .TCH | Micro Focus International plc | Arquivos de dados | Borland C++ Help Document | Borland C++ | Micro Focus International plc |
| .TCL | Open Source | Arquivos de dados | Tcl Script | MacroMates TextMate | MacroMates |
| .TCO | Unknown Developer | Arquivos de dados | T9000 Object Module | Unknown Software | Unknown Developer |
| .TCX | Garmin | Arquivos de dados | Training Center Database File | Garmin Connect | Garmin |
| .TDB | Google | Arquivos de dados | Android Thumbnail Cache | Google Android | Google |
| .TDD | MRDC Software | Arquivos de dados | Tables Direct Template | Tables Direct | MRDC Software |
| .TDF | DVD Copy | Arquivos de dados | Title Definition Format File | DVD X Copy | DVD Copy |
| .TDG | Tom Lachecki | Arquivos de dados | Tree Diagram Generator Document | Tree Diagram Generator | Tom Lachecki |
| .TDH | Borland | Arquivos de dados | Turbo Debugger Help File | Borland Turbo Debugger | Borland |
| .TDK | Borland | Arquivos de dados | Borland Turbo Debugger Keystroke Recording File | Borland Turbo Debugger | Borland |
| .TDN | SoftArtStudio | Arquivos de dados | TreeDBNotes Database | TreeDBNotes | SoftArtStudio |
| .TDR | PO KSI | Arquivos de dados | ArVid Tape Backup | ArVid | PO KSI |
| .TDT | Sony | Arquivos de dados | AVCHD Thumbnail File | Unknown Software | Unknown Developer |
| .TDX | D-TEG Security Co. | Arquivos de dados | D-TEG CCTV Video Information File | D-TEG MRX PC Client | D-TEG Security Co. |
| .TEASERS2 | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TEC | SIL International | Arquivos de dados | TECkit Compiled Mapping File | TECkit | SIL International |
| .TECH | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TEF | tabledit.com | Arquivos de dados | TablEdit Tablature | TuxGuitar | Julian Gabriel Casadesus and Others |
| .TEK | Unknown Developer | Arquivos de dados | ASITIC Technology File | ASITIC | Unknown Developer |
| .TELL | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TEM | E J Software | Arquivos de dados | Badge Designer 2000 Data | Badge Designer 2000 | E J Software |
| .TER | Planetside Software | Arquivos de dados | Terragen Terrain File | Planetside Software Terragen | Planetside Software |
| .TEST | Unknown Developer | Arquivos de dados | Testing File | Unknown Software | Unknown Developer |
| .TESTING | Apple | Arquivos de dados | Golden Orchard Apple II CD Rom File | Apple OS X | Apple |
| .TET | RM Education | Arquivos de dados | Textease CT Template | Textease Studio | RM Education |
| .TEXI | GNU Project | Arquivos de dados | TEXinfo File Format | TexInfo | GNU Project |
| .TFA | Tree Software and Consulting Inc. | Arquivos de dados | TreeSoft CashFlow Analysis Data File | treeSoft CashFlow Analysis (tree.fa.exe) | treeSoft |
| .TFD | Various Developers | Arquivos de dados | Tape Format Requirements Document | BAE Systems VITec PC | BAE Systems |
| .TFH | Borland | Arquivos de dados | Turbo Profiler Help Data File | Turbo Profiler | Borland |
| .TFM | Jonathan Kew and Stefan Löffler | Arquivos de dados | TeX Font Metric File | MiKTeX | Christian Schenk |
| .TFR | LucasArts Entertainment Company, LLC | Arquivos de dados | TIE Fighter Pilot File | Star Wars: TIE Fighter | LucasArts Entertainment Company, LLC |
| .TFS | Borland | Arquivos de dados | Turbo Profiler Statistical Information Data | Turbo Profiler | Borland |
| .TFT | FormatBlue Software | Arquivos de dados | Text Formatter Plus File | Text Formatter Plus | FormatBlue Software |
| .TFU | Two notes Audio Engineering | Arquivos de dados | Torpedo Live Firmware Update | Torpedo Live | Two notes Audio Engineering |
| .TFW | ESRI | Arquivos de dados | World File For TIFF | ESRI ArcGIS for Desktop | ESRI (Environmental Systems Research Institute) |
| .TFX | Avid Technology | Arquivos de dados | Pro Tools Eleven Rack Plugin Preset File | Avid Pro Tools | Avid Technology |
| .TGD | Planetside Software | Arquivos de dados | Terragen Project File | Planetside Software Terragen | Planetside Software |
| .TGF | Unknown Developer | Arquivos de dados | Trivial Graph Format File | Wolfram Research Mathematica | Wolfram Research |
| .TGS | GeneStudio, Inc. | Arquivos de dados | GSTree Phylogenetic Tree Information Data | GeneStudio Pro | GeneStudio, Inc. |
| .TGT | Corel | Arquivos de dados | Corel Custom Data | CorelDRAW Graphics Suite | Corel |
| .TH | Open Source | Arquivos de dados | Therion Data File | Therion | Open Source |
| .THR | PTC | Arquivos de dados | Pro/ENGINEER File | Pro/ENGINEER | PTC |
| .THS | Corel | Arquivos de dados | Corel WordPerfect Thesaurus Dictionary | Corel WordPerfect | Corel |
| .TIA | Siemens AG | Arquivos de dados | Siemens TIA Portal Data | TIA Portal | Siemens AG |
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