| trie | Trie Data |
| trig | RDF Serialization Format Data |
| triggers | Debian Package Triggers Data |
| triple-s | Triple-S Survey Data |
| trix | RDF Triples in XML |
| trj | GROMACS Trajectory of a Simulation Data |
| trk | Garmin GPS PCX5 Tracklog |
| trk | STAR-CD v4 Droplet Track Data |
| trk | Concordance Transaction Tracking Data |
| trk | MakeMusic Finale Track/Staff Mapping File |
| trl | Topocad Roadlines |
| trl | Holux GM-101 Tracklog |
| trm8 | Avantes Avasoft v8 Transmittance Mode Data |
| trn | Oracle Documaker Transaction Data |
| trn | Microsoft SQL Server Transaction Log |
| trn | CFX Transient File |
| trn | PTC Creo Turning Parameter Data |
| tro | IBM Voice Type Data |
| trp | Topocad Road Profile |
| trp | TripMaker Document |
| trp | MotionTracking Track Search Parameters Data |
| trp | TrimeTool TRP Output |
| trr | GROMACS Trajectory File |
| trs | TrIDNet Serialized Definitions Package |
| trs | WinTrack Railroad Track Text Data |
| trs | Table Retrieval System Document |
| trt | Team Sports Scheduling System Report Template |
| truck | Rigs of Rods Truck Description File |
| trv | Topocad Traverse Document |
| trxml | Textkernel Sourcebox XML Data |