| d1 | Progress OpenEdge Database |
| d2 | Progress OpenEdge Database |
| d2e | Gaussian Two-Electron Integral Derivative File |
| d3d | Game Maker 3D Data |
| d3p | DigitalPrintLab 3 Data |
| d7d | Dewesoft 7 Data |
| d7s | Dewesoft 7 Setup Data |
| d7t | Dewesoft 7 Sequence Data |
| d83 | GAEB 1990 Data File |
| da2 | HammerTap DeepAnalysis Save |
| dab | OrangeCD Database |
| daf | Digital Anchor Data |
| dak | Debian Archive Kit Data |
| dal | Download Accelerator Plus List |
| dam | DeltaMaster Analysis Model |
| dan | D-MAS Analysis Data |
| daq | Data Acquisition Toolbox File |
| das | DeltaMaster Analysis Session Data |
| dash | Dashlane Profile |
| dat | Treepad Database |
| dat | General Data File |
| dat | eM Client Database |
| dat | DataFlex Database File |
| dat | Nero BackItUp Drive Image |
| dat | Radiance Data File |
| dat | Affymetrix Image Data File |
| dat-shm | eM Client SHM Data |
| dat-wal | eM Client WAL Data |
| data | General Data File |
| data | Analysis Studio Data |
| database | Serato DJ Database |
| datd | Daily Aggregated Traffic Data |
| datr | DATR Data |
| datt | STK Processed Intermediate Terrain File |
| datx | Canon EOS Utility Data |
