| ndf | Microsoft SQL Server Secondary Database File |
| ndi | Novell Netware Device Information File |
| ndj | Newline Delimited JSON Data |
| ndjson | Newline Delimited JSON Data |
| ndk | Lotus Notes Design Elements |
| ndl | Lotus Notes Data Link |
| ndm | Navicat for MySQL DataModels Data |
| ndots | Ribbons Polygon Definition |
| ndp | NET Deed Plotter File |
| ndpa | Hamamatsu NanoZoomer Annotation Data |
| ndpvs | Hamamatsu NanoZoomer Script |
| ndr | Nikon Capture Image Dust Off File |
| nds | Nintendo DS ROM Image |
| ndt | Niton Data Transfer File |
| ndv | Nanodrop Spectrophotometer Report |
| ndv | SmartWare Network Driver |
| ndx | Aston-Tate dBASE Database Index |
| nec | NEC Antenna Data |
| ned | Navicat for MySQL ER Diagram Data |
| nef | Nero BackItUp Encryption File |
| nei | LonWorks Neuron EPROM Image File |
| nes | NES ROM Image |
| nessus | Nessus Network Security Scanner |
| net | KiCad Netlist Data |
| neta | Netica Binary Data |
| netspm | NetSpot Map |
| newsloc | Mac OS X Finder News Location Data |
| nex | NeuroExplorer Data |
| nex | NEXUS Data File |
| nf | The Bro NetFlow Data |
| nf2 | NeverForget v2 Data |
| nfa | Netflix for Android Data |
| nfb | Nokia Phone Backup |
| nfc | Nokia Phone Backup |
| nfe | Nikon Capture Fisheye Lens Data |