| tdf | DVD X Copy TDF File |
| tdf | Guide Text Definition File |
| tdh | Borland Turbo Debugger Help Data |
| tdo | Xilinx Text Design Output |
| tdp | Serif DrawPlus Thumbnail |
| tdr | Keysight PLTS TDR Calibration Data |
| tdr | TINA Diagram Results |
| tds | Tableau Data Source |
| tdsx | Tableau Packaged Data Source |
| tdt | PLINK Transmission Disequilibrium Test Report |
| tdt | THOR Datatree File |
| tdt1 | AACS Thumbnail Data File |
| tdt2 | AACS Thumbnail Data File |
| tdump | JIRA Thread Dump |
| tdv | NI Diadem Layout |
| te | Textease Database CT Single-user Database |
| te1 | UltraEdit Template |
| te3 | WinTrack Object File |
| tea | TEA Encrypted Data |
| teacher | SMART Response Teacher Database |
| tec | TECkit Compiled Mapping Table |
| tei | TrackEye Image Sequence Data |
| tek | Tektronix HEX Data |
| teo | TruTops Tube Data |
| teq | TINA Equation File |
| ter | Terragen Terrain File |
| term | Apple Terminal Data |
| terrain | Terragen Terrain File |
| terrn | Rigs of Rods Terrain Data |
| terrn2 | Rigs of Rods Terrain Data |
| tet | Textease Database CT Single-user Database Template |
| tew | Bentley InRoads Text Export Wizard Data |
| texter | Texter Snippet Data |
| textfactory | BBEdit Text Factory Data |
| tf10 | IRIG 106 Data Transfer Data |