| dek | Memorize-It Deck File |
| del | Lucene Deleted Documents Data |
| den | XMVB Density Data |
| deploy | ClickOnce Deployment Data |
| det | Act! Email Message |
| deu | Adobe Acrobat Reader German Language Data |
| devx | E-Sword Devotional Data |
| dez | DataEase v4 Data File |
| df | Lightscape Parameter File |
| df | Paradox Table Filter |
| df7 | Omnis Studio v7 Database |
| dfa | SecuROM Manual Activation Request. |
| dfd | qs-STAT Q-DAS Description File |
| dfi | TI bqEASY Data Flash Image |
| dfp | Data Flask Package |
| dfq | qs-STAT Q-DAS Shared Data File |
| dfq | SmartWare Query Definition File |
| dfr | DataFlex Registration Data |
| dfr | SmartWare Report Definition File |
| dfs | BrainSuite Surface |
| dfs | SmartWare Sort Definition File |
| dft | EES Default Information |
| dft | SmartWare Transact Definition File |
| dfv | Microsoft Word Print Format Template |
| dfw | SmartWare Cross-Tab Definition File |
| dfw | Derive for Windows Data |
| dfx | qs-STAT Q-DAS Value File |
| dfx | SmartWare Relate Definition File |
| dfxml | Digital Forensics XML |
| dgb | Digitarch FlashCAD Drawing Database |
