| t2flow | Taverna v2 Workbench Workflow Definition |
| t2g | Kallisto Transcript to Gene Data |
| t2k | Teach2000 Document |
| t2ks | Teach2000 Student Answers File |
| t2kt | Teach2000 Exam File |
| t2s | Tier2 Submit Data |
| t32 | PowerQuest Drive Image 5 Data |
| t3a | Swift 3D Animation Preset Data |
| t3d | TicTacTi Advertisement Definition |
| t3g | Sunpinyin Data |
| t44 | dBASE IV Temporary Data |
| t4l | TommySoftware CAD Biblio Dat |
| t81 | EightyOne ROM Image |
| t88 | NEC PC-88 Tape Data |
| t99 | TaxCut Federal Data |
| ta | Sony Xperia Flash Tool Trima Area Data |
| ta1 | TaxACT 2001 Tax Return Data |
| ta2 | TaxACT 2012 Tax Return Data |
| ta2m | SAM Trimmed Alignment Data |
| ta3 | TaxACT 2013 Tax Return Data |
| ta4 | TaxACT 2014 Tax Return Data |
| ta5 | TaxACT 2015 Tax Return Data |
| ta6 | TaxACT 2016 Tax Return Data |
| ta7 | TaxACT 2017 Tax Return Data |
| ta8 | TaxACT 2008 Tax Return Data |
| ta9 | TaxACT 2009 Tax Return Data |
| tab | ArcInfo Lookup Data |
| tab | SQL Script Tables |
| tabrpt | CommScope Teletilt Control System Tabbed Site Report File |
| tac | ActiCalc Data |
| tacx | Tacx Exported Training Data |
| tad | TA Orchestrator Data |
| taf | ADRIFT Text Adventure File |
| tag | DataFlex Query Tag |
| tags | abcAVI Tag Editor Tags Data |