| tkb | TicketBench Data |
| tkc | MetaTrader 5 Tick Data |
| tkd | Wikit TKD Database |
| tkfl | TKLinks Saver Favorite Links |
| tki | Tkined Data |
| tks | NI Traktor Pro MIDI Map |
| tkt | TK Solver Data |
| tkw | TK Solver Data File |
| tkx | TK Solver Package |
| tl5 | Timeliner 5 Data |
| tlb | HP OpenVMS Text Library |
| tlbackup | True Launch Bar Settings Backup |
| tlbbackup | True Launch Bar Settings Backup |
| tlbplugin | True Launch Bar Plugin |
| tlc | TINA Logic Converter Data |
| tld | PTC Creo Thermal Temperature Load Data |
| tld | TINA Library Descriptor |
| tle | STK Two-line Element Sets |
| tlf | Timing Library Format File |
| tlist | Geomview Transformation Matrices Data |
| tll | LG TV Link-Loader File |
| tlm | Spektrum DX8 Telemetry Log |
| tln | HyperLynx LineSim Schematic |
| tlo | SPSS Table Look File |
| tlog | ArduCopter Telemetry Log |
| tlog | Oracle Database Transaction Log |
| tlr | Tableau Offline License Registration Data |
| tlsv | Topcon TopSURV Database |
| tlt | Trellix Web Design File |
| tlx | CuteSITE Builder Website Data |
| tly | Adobe Photoshop Elements Backup Catalog |
| tlz | LZMA Compressed TAR Archive |
| tlzma | LZMA Compressed TAR Archive |
| tm | Catalyst Translation Memory Data |
| tm1 | TimeWise Data |