| 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 | Protector Suite QL Encrypted Data |
| fdp | Viamichelin Map File |
| fdpart | Fresh Download Partial Downloaded File |
| fdr | Windows Error Report |
| fdrp | Mac OS X Folder Alias Data |
| fdrtemplate | FDRTools Template |
| fds | Fire Dynamics Simulator Data |
| fds | FME Desktop Format Data |
| fds | JetForm FormFlow Data |
| fds | NES FDS Image |
| fdsrch2 | FeedDemon Search Data |
| fdt | Impromptu Function Description Table |
| fdt | Lucene Field Data |
| fdt | Natural Field Definition Table |
| fdt | Visilogic Utilities Full Data Table |
| fdu | Natural ADAFDU Data |
| fdx | Food Data Exchange File |
| fdx | Lucene Field Index |
| fdxsl2 | FeedDemon Newspaper Style |
| fdxsl4 | FeedDemon Newspaper Style |
| fe | Surface Evolver Data File |
| fea | AFDKO Feature Definitions File |
