| Extension | File Description |
| .DEFAULT | Uncommon Files |
| .DEFAULTS | Uncommon Files |
| .DEFENSE | Uncommon Files |
| .DEFI | Uncommon Files |
| .DEFS | Uncommon Files |
| .DEG | Uncommon Files |
| .DEH | Uncommon Files |
| .DEI | Uncommon Files |
| .DEJ | Uncommon Files |
| .DEJAVU-THE | Uncommon Files |
| .DEK | Game Files |
| .DEL | Uncommon Files |
| .DELAY | Uncommon Files |
| .DELETE | Uncommon Files |
| .DELTA | Uncommon Files |
| .DEM | Game Files |
| .DEMO | Uncommon Files |
| .DEMO2 | Uncommon Files |
| .DEMOPIC | Uncommon Files |
| .DEN | Uncommon Files |
| .DEO | Uncommon Files |
| .DEP | Developer Files |
| .DEPLOY | Uncommon Files |
| .DEPOT | Uncommon Files |
| .DEPR | Uncommon Files |
| .DEPRO | Uncommon Files |
| .DEPROTECT | Uncommon Files |
| .DEPROTECTS | Uncommon Files |
| .DEQ | Uncommon Files |
| .DER | Web Files |
| .DES | CAD Files |
| .DESC | Game Files |
| .DESCR | Uncommon Files |
| .DESD | Uncommon Files |
| .DESIGN | Vector Image Files |
| .DESK | Uncommon Files |
| .DESKEDIT | Uncommon Files |
| .DESKLINK | System Files |
| .DESKTOP | Misc Files |
| .DESKTRCKR | Uncommon Files |
| .DET | Uncommon Files |
| .DETAILS | Uncommon Files |
| .DETECTOR | Uncommon Files |
| .DEU | Uncommon Files |
| .DEV | Developer Files |
| .DEVEL | Uncommon Files |
| .DEVHELP | Uncommon Files |
| .DEVIATION | Uncommon Files |
| .DEVLIST | Uncommon Files |
| .DEW | Uncommon Files |
| .DEWF | Audio Files |
| .DEX | Spreadsheet Files |
| .DEY | Uncommon Files |
| .DEZ | Uncommon Files |
| .DE_ | Uncommon Files |
| .DF | Uncommon Files |
| .DF$ | Uncommon Files |
| .DF0 | Uncommon Files |
| .DF1 | Developer Files |
| .DF10 | Uncommon Files |
| .DF2 | Audio Files |
| .DF3 | Uncommon Files |
| .DF4 | Uncommon Files |
| .DF5 | Uncommon Files |
| .DF6 | Uncommon Files |
| .DF7 | Uncommon Files |
| .DF8 | Uncommon Files |
| .DF9 | Uncommon Files |
| .DFA | Uncommon Files |
| .DFAC | Executable Files |
| .DFB | Uncommon Files |
| .DFC | Audio Files |
| .DFCLASS | Uncommon Files |
| .DFCOMPONEN | Uncommon Files |
| .DFD | Uncommon Files |
| Extension | File Description |
| .DFE | Uncommon Files |
| .DFF | 3D Image Files |
| .DFG | Uncommon Files |
| .DFH | Uncommon Files |
| .DFI | Uncommon Files |
| .DFJ | Uncommon Files |
| .DFK | Uncommon Files |
| .DFL | Uncommon Files |
| .DFM | Data Files |
| .DFN | Uncommon Files |
| .DFO | Uncommon Files |
| .DFONT | Font Files |
| .DFP | Plugin Files |
| .DFPACKAGE | Uncommon Files |
| .DFQ | Uncommon Files |
| .DFR | Uncommon Files |
| .DFS | Uncommon Files |
| .DFSEQUENCE | Uncommon Files |
| .DFT | CAD Files |
| .DFU | Uncommon Files |
| .DFV | Uncommon Files |
| .DFW | Uncommon Files |
| .DFWEBAPPLI | Uncommon Files |
| .DFX | CAD Files |
| .DFY | Uncommon Files |
| .DFZ | Uncommon Files |
| .DG | Uncommon Files |
| .DG-KEY | Uncommon Files |
| .DG0 | Uncommon Files |
| .DG1 | Uncommon Files |
| .DG2 | Uncommon Files |
| .DG3 | Uncommon Files |
| .DG4 | Uncommon Files |
| .DG5 | Uncommon Files |
| .DG6 | Uncommon Files |
| .DG7 | Uncommon Files |
| .DG8 | Uncommon Files |
| .DG9 | Uncommon Files |
| .DGA | Uncommon Files |
| .DGB | Uncommon Files |
| .DGC | Compressed Files |
| .DGD | Uncommon Files |
| .DGE | Uncommon Files |
| .DGF | Uncommon Files |
| .DGG | Uncommon Files |
| .DGH | Uncommon Files |
| .DGI | Uncommon Files |
| .DGJ | Uncommon Files |
| .DGK | CAD Files |
| .DGL | Uncommon Files |
| .DGM | Uncommon Files |
| .DGMARKER | Uncommon Files |
| .DGN | CAD Files |
| .DGO | Uncommon Files |
| .DGP | Uncommon Files |
| .DGPRINT | Uncommon Files |
| .DGQ | Uncommon Files |
| .DGR | Uncommon Files |
| .DGS | Data Files |
| .DGSCHEME | Uncommon Files |
| .DGSCHEME-W | Uncommon Files |
| .DGSS | Uncommon Files |
| .DGT | Uncommon Files |
| .DGTOOLBAR | Uncommon Files |
| .DGU | Uncommon Files |
| .DGV | Uncommon Files |
| .DGW | Uncommon Files |
| .DGX | Uncommon Files |
| .DGY | Uncommon Files |
| .DGZ | Uncommon Files |
| .DH | Uncommon Files |
| .DH0 | Uncommon Files |
| .DH1 | Uncommon Files |
| .DH2 | Uncommon Files |
| .DH3 | Uncommon Files |
