| dat-wal | eM Client WAL Data |
| dat2 | XYplorer Thumbnail Cache |
| data | Analysis Studio Data |
| data | General Data File |
| database | Serato DJ Database |
| datd | Daily Aggregated Traffic Data |
| datr | DATR Data |
| datt | STK Processed Intermediate Terrain File |
| datx | Canon EOS Utility Data |
| dau | SPSS Overflow Data |
| day | WRAP DAY Output Data |
| da_ | Compressed DAT File |
| db | General Database File |
| db-shm | SQLite Database Shared Memory |
| db-wal | SQLite Database Write-Ahead Log |
| db1 | Tekla Structures Model |
| db2 | dBASE II Database |
| db2 | Tekla Numbering Database |
| db2ind | Microsoft Visual Studio DB2 Index Data |
| db3 | Berkeley DB3 Database |
| db3-wal | SQLite 3 Write-Ahead Log |
| db4 | dBASE IV Database |
| dba | Steinberg WaveLab Audio Database |
| dban | DBAN Data |
| dbas | AQUA Database |
| dbb | Skype Binary Log File |
| dbc | DAZ Studio Brick Camera |
| dbc | Microsoft Visual FoxPro Database |
| dbdif | DatabaseSpy Comparison Data |
| dbe | ActiveSync Backup |
| dbg | SOBEK Debug Data |
| dbgconf | Keil ULINK2 Debug Configuration Data |
| dbheader | Download Boost Header Data |
| dbi | Treepad Database DBI Data |
| dbin | ACDSee Pro Database |