| fdb | Portfolio Catalog Data |
| fdc | Autodesk AutoCAD Fields Description |
| fdc | McAfee Sniffer Capture Data |
| fdd | FlexiDATA Database |
| fde | AFP Form Definition |
| fde | FLAMES Dataset Export Data |
| fdf | Format Description File |
| fdf | Origin Fitting Function Definition File |
| fdff | Fast Duplicate File Finder Data |
| fdi | FormDocs Index |
| fdk | Fluentizer Dictionary Data |
| fdlang2 | FeedDemon Language Data |
| fdlang4 | FeedDemon Language Data |
| fdm | Microsoft Exchange Server Form Message Data |
| fdm | SIPINA FDM Data |
| fdn | MODFLOW Drawdown Data |
| fdo | ModelSim Script |
| fdp | Epson PhotoQuicker Frame |
| fdp | Viamichelin Map File |
| fdpart | Fresh Download Partial Downloaded File |
| fdrp | Mac OS X Folder Alias Data |
| fdrtemplate | FDRTools Template |
| fds | Fire Dynamics Simulator Data |
| fds | FME Desktop Format Data |
| fds | JetForm FormFlow Data |
| fdsrch2 | FeedDemon Search Data |
| fdt | Impromptu Function Description Table |
| fdt | Lucene Field Data |
| fdt | Natural Field Definition Table |
| fdt | Visilogic Utilities Full Data Table |
