| traw | PLINK Variant-major Additive Component File |
| tray | Corel CONNECT Tray |
| trb | HP Printer Diagnostic Package |
| trbw | STAR-CCM+ TurboWizard File |
| trc | Lattice Reveal Analyzer Waveform Data |
| trd | TrID Definitions Package |
| tree | Es-Builder v3 Tree File |
| treefile | GDE Phylogenetic Tree Data |
| trf | LFToolkit Transformation Rules File |
| trf | BrainVoyager QX Transformations Data |
| trg | SQL Script Triggers |
| tri | Ribbons Triangle Definition |
| trie | Trie Data |
| triggers | Debian Package Triggers Data |
| triple-s | Triple-S Survey Data |
| trj | GROMACS Trajectory of a Simulation Data |
| trk | MakeMusic Finale Track/Staff Mapping File |
| trk | STAR-CD v4 Droplet Track Data |
| trk | Garmin GPS PCX5 Tracklog |
| trl | Holux GM-101 Tracklog |
| trl | Topocad Roadlines |
| trn | PTC Creo Turning Parameter Data |
| trn | CFX Transient File |
| trn | Oracle Documaker Transaction Data |
| trn | Microsoft SQL Server Transaction Log |
| tro | IBM Voice Type Data |
| trp | TripMaker Document |
| trp | TrimeTool TRP Output |
| trp | MotionTracking Track Search Parameters Data |
| trp | Topocad Road Profile |
