| ndb | ClamAV Extended Signature Data |
| ndb | NEPLAN Network Node Data |
| ndd | Nikon Capture Dynamic Exposure Extender |
| ndf | Channel Data File |
| 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 |
| ndpr | Hamamatsu NanoZoomer Digital Pathology Image Format Data |
| ndpvs | Hamamatsu NanoZoomer Script |
| ndr | Nikon Capture Image Dust Off File |
| nds | Nintendo DS ROM Image |
| ndt | NEPLAN External Program Data |
| ndt | Niton Data Transfer File |
| ndu | SymbianOS Backup Data |
| ndv | Nanodrop Spectrophotometer Report |
| ndv | SmartWare Network Driver |
| ndx | Aston-Tate dBASE Database Index |
| ndx | Concordance Numeric Data and Text Fields Data |
| ndx | Neat 5 Exported Archive |
| nearest | PLINK Nearest Neighbor Distance Report Data |
| neb | Nord Electro 3 Factory Backup |
| nec | NEC Antenna Data |
| ned | Navicat for MySQL ER Diagram Data |
| nef | Nero BackItUp Encryption File |
| nei | LonWorks Neuron EPROM Image File |
| neon | NEON Encoded Data |
| nepg | Nord Electro 3 Program |
| nes | NES ROM Image |
